Question

Check my answer-
Solve the system of equations algebraically. Show all of your steps.
Y=x^2+2x
Y=3x+20

My answer:
X^2+2x+3x+20
X^2-x-20
(x-5),(x+4)=0
x=5, x=-4
y=35, y=8

Thank you!

Answer 1

No, you might have come up mysteriously with the answer but it does not follow from what you did.

You start off with two lines are are not equations,
X^2+2x+3x+20
X^2-x-20 ----> this does not follow from the previous line,
then in the third line all of a sudden you have
.... = 0

proper way:
x^2 + 2x = 3x + 20 , since Y = Y
x^2 - x - 20 = 0
(x-5)(x+4) = 0
x = 5 or x =-4

if x = 5, y = 3(5) + 20 = 35
if x = -4, y = 3(-4) + 20 = 8