Question

solve simultaneous equations x-y=2 and xy=15

Answer 1

Answer:

x=5,  y=3

x=-3, y=-5

Step-by-step explanation:

Explained in pic, step by step

Answer 2

xy=15

x = 15/y

x-y=2

15/y - y = 2

15 - y² = 2

y

15 - y² = 2y

15 - y² - 2y =0

-y² - 2y + 15 = 0

y² + 2y - 15 = 0

y² -3y + 5y - 15 = 0

y(y - 3) + 5(y - 3) = 0

(y + 5) (y - 3) = 0

y + 5 = 0 y -3 =0

y = -5 y = 3

y = -5 or 3