Question

Find the solutions to the system; y=x^2-3x-1 and y=8x-1

a) (0,-1) and (11,388)

b) (0,-1) and (11,87)

c) (-1,0) and (87,11)

d) no solution


I know the first step is to make them equal to each other, x^2-3x-1=8x-1

Answer 1

x^2-3x-1=8x-1
x^2-3x-8x+1-1=0
x^2-11x=0
x(x-11)=0

x=0 or x=11

when x=0, y=-1
x=11, y=8*11-1, y=87
⇒ b is the answer