You want the y value of one equation to be equal to the y of the other, so
x^2 + 2x = 3x +20
x^2 - x - 20 = 0
which factors nicely to
(x-5)(x+4) = 0
so x = 5 or x = -4
sub those x values into either equation to get the corresponding y values
Solve the system of equations algebraically. Show all of your steps.
y=x^2+2x
y=3x+20
1 answer