Answer: 25
Step-by-step explanation: (x-a)² = x² - 2ax + a²
From x² - 10x + k we deduce that 10x = 2·5x and a = 5
Then k = 5²2
y=
x+y=
Answer:
4
Step-by-step explanation:
Simplify x and y by rationalising the denominator of both
To rationalise the denominator multiply the numerator/ denominator by the conjugate of the denominator.
The conjugate of 2 + is 2 -
The conjugate of 2 - is 2 +
x = = = 2 -
y = = = 2 +
Thus
x + y = 2 - + 2 + = 4