I am currently taking a practice test. The question is to find the x and y intercepts of the graph y=3x^2+6x-9. They say that the answer is x=-3 or x=2 and y=(0,-9). I get that x=1 or x=-3 and y=-9. What did i do wrong?

Question

I am currently taking a practice test.  The question is to find the x and y intercepts of the graph y=3x^2+6x-9.  They say that the answer is x=-3 or x=2 and y=(0,-9).  I get that x=1 or x=-3 and y=-9.  What did i do wrong?

.sam. · Answer

y-intercept when x=0
y=-9
(0,9)

anonymous · Answer

Right.

.sam. · Answer

x-intercept when y=0
x=-3,1
(-3,0) and (1,0)

across · Answer

You are given $f(x)=3x^2+6x-9$. To find the $x$-intercepts, you have to set $3x^2+6x-9=0\implies3(x-1)(x+3)=0\implies x=1\text{ and }x=-3$. To find the $y$-intercept, you evaluate the function at $0$: $f(0)=-9$.

anonymous · Answer

Thank You.  I thought that I was going crazy... Thank you!