MATHEMATICS HIGH SCHOOL

What is

3x-2y=9
y=2x-7

Answers

Answer 1
Answer: Okay, these get easy with practice so don't post all of these online. First, substitute y in 3x-2y=9 for what it says y equals (2x-7). You now have: 3x-2(2x-7)=9. Breakdown:
3x-2(2x-7)=9
3x-4x+14=9
-1x=-5
x=5
next solve for y
y=2x-7
y=2(5)-7
y=10-7
y=3
And now we have x=5, and y=3.
Answer 2
Answer: Since you know that "y" is equivalent to "2x - 7" you can substitute that into the first equation

3x - 2y = 9
3x - [2(2x-7)]= 9
3x - (4x - 14) = 9
3x - 4x + 14 = 9
-x + 14 = 9
-x = -5
x = 5


y = 2x - 7 
y = 2(5) - 7
y = 10 - 7
y = 3

Related Questions

Aaron is 15 centimeters taller than Peter, and five times Aaron's height exceeds two times Peter's height by 525 centimeters.The system of linear equations that relates Aaron's height (x) and Peter's height (y) is given by . Aaron's height is centimeters, and Peter's height is centimeters.
5x+y=2 find an order pair for x,y
At the register Annie notices her grocery bill was marked with $14 for the 7 pounds of meat she purchased. What is another wayof saying this ratio?
Is it true that a line with slope 1 always passes through the origin? Explain your reasoning.
Simplify and solve this equation: 4m + 9 + 5m – 12 = 42.A. m = -4B. m = 4C. m = –5D. m = 5

A cell phone plan has a monthly cost that is shown in the table below. What is the correct statement regarding the average rate of change during the 40-minute time of talk?Total minutes of talk time Monthly cost of cell phone
0 $19.95
10 $20.45
20 $20.95
30 $21.45
40 $21.95


A.) The average rate of change is $0.50, meaning that for each minute of talk time, the monthly bill increases by $0.50.

B.) The average rate of change is $0.50, meaning that for every ten minutes of talk time, the bill increases by $0.50.

C.) The average rate of change is $0.05, meaning that for each minute of talk time, the monthly bill increases by $0.05.

D.) The average rate of change is $0.05, meaning that for every ten minutes of talk time, the bill increases by $0.05.

Answers

For this case, the first thing we must do is find the average rate of change for the mentioned interval.

By definition we have to:

AVR = (f(x2)-f(x1))/(x2-x1)

Substituting values we have:

AVR = (21.95-19.95)/(40-0)

Rewriting we have:

AVR = (2)/(40)

Answer:

C.) The average rate of change is $0.05, meaning that for each minute of talk time, the monthly bill increases by $0.05.

The answer would be B The average rate of change is $0.50, meaning that for every ten minutes of talk time, the bill increases by $0.50. 

The diagram shows a vertical tower DC on a horizontal ground ABC. ABC is a straight line.

The angle of elevation of D from A I'd 28°.

The angle of elevation of D from B is 54°.

AB=25m

Calculate the height of the tower.

Give your answer in 3 significant figures.

I need working out. Plz help me.

Answers

the measure of ABD=180°- 54°=26°
and then the measure of ADB= x
and x + 26° + 28°= 180°, sum of anlgle in a triagle property
 it means x= 180°- 26-28=126°
application of sinus law in the triangle

sin 28 / BD = sin 126/ AD = sin 26/ 25 so we can deduce that 

AD= 25sin126 / sin26= 46.12
let 's consider the triangle ADC, so for finding h, we have sin 28 = h / AD
and then h = AD x sin28=21.65

Calculate the height of the tower is 21.65

If f(x) = 3x and g(x)=2x, what is (g o f)(x)?
5x
5x2
6x
6x2

Answers

If you would like to solve (g ° f)(x), you can calculate this using the following steps:

(g ° f)(x) = g(f(x))

(g ° f)(x) = g(f(x)) = g(3x) = 2 * 3x = 6x

The correct result would be 6x.

Find the value of r so the line that passes through each pair of points has the given slope.40. In 1991, the federal minimum wage rate was $4.25 per hour. In 1997, it was increased to $5.15. Find the annual rate of change in the federal minimum wage rate from 1991 to 1997.

41. (6,2), (9,r), m=-1

42. (4,-5), (3,r), m=8

43. (5,r), (2,-3), m=4/3

44. (-2,7), (r,3), m=4/3

45. (1/2, -1/4), (r,-5/4), m=4

46. (2/3, r), (1,1/2), m= 1/2

47. (4,r), (r,2), m=-5/3

48. (r, 5), (-2, r), m=-2/9

Answers

Slope is rise over run.
40. the rise is $0.90 and the run is 6 years, so the annual rate of change is .9/6 = $0.15 per year
40) Final answer: $0.15 per year

For 41-48, find the difference between the given values of the same variable, then multiply by the slope and add/subtract from the variable whose second value is missing (sorry if that's confusing)
41. 9-6=3 => 3*(-1)=-3 => 2+3=-1
41) Final answer: r=-1
42. 4-3=1 => 1*8=8 => (-5)-8=-13
42) Final answer: r=-13
43. 5-2=3 => 3*(4/3)=4 => -3+4=1
43) Final answer: r=1
44. 7-3=4 => 4*(3/4)=3 (flip the slop to find x values) => -2-3=-5
44) Final answer: r=-5
45. (-1/4)-(-5/4)=4/4=1 => 1*(1/4)=1/4 (again flip the slope) => 1/2-1/4=1/4
45) Final answer: r=1/4
46. 1-(2/3)=1/3 => (1/3)*(1/2)=(1/6) (don't have to flip this time) => (1/2)-(1/6)=1/3
46) Final answer: r=1/3
For 47 and 48, I'll setup an equation for r
47. (4-r)*(-5/3)=r-2 => -20/3+(5r)/3=r-2 => -14/3+(5r)/3=r => -14/3=-(2r)/3 => -14=-2r => r=7
47) Final answer: r=7
48. (R-(-2))*(-2/9)=5-r => -2(r+2)/9=5-r => -(2r)/9-4/9=5-r => -(2r)/9=49/9-r => (7r)/9=49/9 => 7r=49 => r=7
48) Final answer: r=7

Hope I helped :)

WOULD YOU RATHER use a coupon for $20 off 10of your order OR use a coupon for 20% off of your order?Use mathematics to justify your answer.

Answers

Answer:

Well it would depend on the price

Step-by-step explanation:

if it was for $100 item , these are the same but, if its more, the 20% will be higher off the bigger the price

so I would much rather have 20% off for and item more than 100 dollars and prefer 20$ off to something under a $100

In a factory, an assembly line can manufacture 39 widgets per second. In another factory, 6 widgets are combined to make 1 whoozit. Approximately how many days must the widget assembly line run to produce 3,500,000 whoozits?A.4 days
B.6 days
C.374 days
D.9479 days

Answers

Given:
39 widgets per seconds
6 widgets to make 1 whoozit

3,500,000 whoozits * 6 widgets/whoozits = 21,000,000 widgets
21,000,000 widgets / 39 widgets/sec = 538,461.54 seconds

1 day = 24 hours
1 hour = 60 minutes
1 minutes = 60 seconds
1 hour = 3600 seconds

3,600 seconds * 24 hrs = 86,400 seconds 
538,461.54 seconds / 86,400 seconds per day = 6.23 days.

B. 6 days.
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