Question

What are the x and y intercepts of y = 2(x+3)^2 - 1?

Answer 1

x-intercept is when y = 0
y-intercept is when x = 0

Answer 2

You can get the y-intercept by substituting 0 for x

You can get the x-intercept by putting the equation equal to zero and then either factoring, using the quadratic formula, or guessing and checking. Since it's a quadratic equation, there will be 2 x-intercepts, so make sure if you choose to guess and check you find 2 numbers that work

Answer 3

y intercept is (0, 17).

Answer 4

I couldn't find the x intercept though? Y doesn't touch 0.

Answer 5

Are these right?

Answer 6

0= 2(x+3)^2 - 1
0=2(x^2+6x+9)-1
0=2x^2+12x+17
\[\frac{ (-12)\pm \sqrt{12^{2}-4(2)(17} }{ 2(2) }\]

Answer 7

That should gve you the 2 x intercepts

Answer 8

\[\frac{ -12\pm \sqrt{8} }{ 4 }\]

(-2.3, 0), (-3.7, 0)?

Answer 9

You could also just keep them in the form with the square root (just be sure to divide by 4 so that it's in its simplest form).

Answer 10

Okay, but the answers i put would be right?

Answer 11

Yup

Answer 12

Thanks, if you don't mind, would you help me with the intervals increasing and decreasing?

Answer 13

Sure! It may be a bit slow though, I'm cooking....

Answer 14

The vertex is -3, so your decreasing interval is negative infinity ----> -3 And you increasing interval is -3 -------> infinity

Answer 15

Thank you!