Question 223459
how do you solve 5y^4-7=73


{{{5y^4-7=73}}}

{{{5y^4 - 80 = 0}}}

{{{5(y^4 - 16) = 5(0))}}} ----- Factoring out the GCF, 5 

{{{(y^2 - 4)(y^2 + 4) = 0}}} ------ Factoring {{{y^4 - 16}}}

{{{(y - 2)(y + 2)(y^2 + 4) = 0}}} ------ Factoring {{{y^2 - 4}}}


{{{y - 2 = 0}}}   ;   {{{y + 2 = 0}}}   ;   {{{y^2 + 4 = 0}}}


{{{highlight_green(y = 2)}}} or {{{highlight_green(y = - 2)}}} or {{{y^2 = - 4}}} ----- {{{sqrt(y^2) = sqrt(-4)}}} ------ {{{y = sqrt(- 1*4)}}} ------ {{{y =_+- sqrt(- 1*2^2)}}} ----- {{{highlight_green(y = 2i)}}} or {{{highlight_green(y = - 2i)}}}