Question

What is the solution set to the system of equations

10x+3y=43
-9x-y=-20

a.) (11,1)
b.) (1,11)
c.) (-1,11)
d.) (11,-1)

Answer 1

10x+3y=43
-9x-y=-20
From second equation,
y=-9x+20
Substitute third equation into first equation,
10x+3(-9x+20)=43
10x-27x+60=43
-17x=43-60
-17x=-17
x=1
y= -9+20= 11
Option B