Question

List the (x)-intercepts and test for symmetry
a.)y=x^4-20x^2-125
b.)x^2+4y^2=4

Answer 1

@jim_thompson5910 Could you help me with this?

Answer 2

to find the x-intercepts, you plug in y = 0 and solve for x

Answer 3

y=x^4-20x^2-125

0=x^4-20x^2-125

0 = z^2 - 20z - 125 ... I'm letting z = x^2, so z^2 = x^4

z^2 - 20z - 125 = 0

solve for z to get ???

Answer 4

wait how do i solve for z?

Answer 5

have you learned about the quadratic formula?

Answer 6

ohh yeah I forgot about that

Answer 7

i'll try it now using it

Answer 8

I got x-25 and x=-5

Answer 9

It's z, not x. Reject z =-5 because z = x^2 , it can't be negative,
--> just take z = 25 --> x^2 =25 , solve for x