How do you factor 5x^4 + 2x^2 - 7?
2 Answers
Aug 11, 2018
Explanation:
because,
Further,
Thus,
Aug 11, 2018
Explanation:
"let "x^2=u
=5u^2+2u-7
"factor the quadratic using the a-c method"
"the factors of the product "5xx-7=-35
"which sum to "+2" are "-5" and "+7
"use these factors to split the middle term"
5u^2-5u+7u-7larrcolor(blue)"factor by grouping"
=color(red)(5u)(u-1)color(red)(+7)(u-1)
"take out the "color(blue)"common factor "(u-1)
=(u-1)(color(red)(5u+7))
"change u back to "x^2
=(x^2-1)(5x^2+7)
(x^2-1)" is a "color(blue)"difference of squares"
=(x-1)(x+1)(5x^2+7)