Question

Please Please Please help.

Solve the system by the substitution method.

x2 + y2 = 113
x + y = 15
A. {( -8, 7), ( -7, 8)}

B. {( 8, -7), ( 7, -8)}

C. {( 8, 7), ( 7, 8)}

D. {( -8, -7), ( -7, -8)}

Answer 1

In the second equation, y = -x - 15

Therefore,

x² + (-x-15)² = 113

x² + (-x - 15)(-x - 15) = 113

x² + x² + 30x + 225 = 113

2x² + 30x + 112 = 0

2(x² + 15x + 56) = 0

2(x + 8)(x + 7) = 0

x = -8, -7

If x = -8, then
-8 + y = -15
So y = -7
So a solution is (-8, -7)

If x = -7, then
-7 + y = -15
y = -8

So a solution is (-7, -8)

So yeah, the solution is (b).

Answer 2

i mean d

Answer 3

Okay thank you so much, you are awesome.