This is an example of the Associative Property of addition.
Solution:
Given that equation is:
Roots are:
To find: value of x
The general quadratic equation is:
From given,
a = 1
b = -k
c = 28
Therefore,
Given roots are:
Therefore,
The two roots are two numbers whose difference is 3 and whose product is 28
Those two roots are 4 and 7 or -4 and -7
Then, sum of roots are:
4 + 7 = 11
-4 - 7 = -11
Therefore, the possible values of k are -11 and 11
Carlos is 6
let x be Carlo's age then
2x + 8 = 20 → (solve for x)
subtract 8 from both sides
2x = 20 - 8 = 12
divide both sides by 2
x = = 6
Carlos is 6 years old
c = Carlos
j = John
--------------------
2c + 8 = j
2c + 8 = 20
2c = 20 - 8
2c = 12
c = 12 : 2
c = 6
-------------------------
6*2+8=20