Question

What are the solutions of the equation 9x4 - 2x2 - 7 = 0? Use u substitution to solve.

Answer 1

9t +7 = 0

t-1 =0

solve for both giving

t = -7/9

t = 1

then we have to plug that back in to u which is x^2

so x^2 = (-7/9)^2 = -1

x^2 = 1

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