1) a^2+2ab+b^2=25, find a+b

All values of a+b are ...

2) a^2-8ab+16b^2=81, find a-4b

All values of a-4b are ...

1) - 5 and + 5; 2) - 9 and + 9

Step-by-step explanation:

1) a² + 2ab + b² = 25

(a + b) ² = 25 Wrote the left-hand side as a square

a + b = ±5 Took the square root of each side

All values of a + b are - 5 and + 5.

2) a² - 8ab + 16b² = 81

(a - 4b) ² = 81 Wrote the left-hand side as a square

a - 4b = ±9 Took the square root of each side

All values of a - 4b are - 9 and + 9.