Question

solve algebraically. y=x^2 and 7x-y=12

Answer 1

Substitute y=x^2 into 7x-y=12

7x-x^2=12
0=x^2-7x+12 This equation can be re-written as follows:
x^2-7x+12=0 Factor this equation
(x-4)(x-3)=0
x=4 and y=16 Because y=x^2=(4)^2=16
x=3, y=9

To check the answer substitute x=4 and y=16 into 7x-y=12
and substitute x=3 and y=9 into 7x-y=12
and in both cases you will get the equation 7x-y equal to 12