How do you simplify #9x^2-5x^4#? Algebra Expressions, Equations, and Functions Variable Expressions 1 Answer Alan P. Sep 28, 2015 Answer: #9x^2-5x^4 = x^2(3-sqrt(5)x)(3+sqrt(5)x)# Explanation: #9x^2-5x^2# #color(white)("XXX")#extracting the obvious factor of #x^2# #=x^2(9-5x^2)# #color(white)("XXX")#remember that #(a^2-b^2) = (a-b)(a+b)# #color(white)("XXX")#and substituting #9 = 3^2# for #a^2# #color(white)("XXX")#and #5x^2 = (sqrt(5)x)^2# for #b^2# #=x^2(3-sqrt(5)x)(3+sqrt(5)x)# Related questions How do you write the variable expression for: a quotient of 2 and the sum of a number and 3 ? What are variables? What are variable expressions? How do you write variable expressions? How do you evaluate variable expressions? How do you simplify the expression #3x-x+4#? How do you write a quotient of a number and 6 as an expression? How do you evaluate the expression #2x+1# for #x=1#? How do you write a product of a number and 2 as an expression? How do you write 5 less than 2 times a number as a variable expression? See all questions in Variable Expressions Impact of this question 281 views around the world You can reuse this answer Creative Commons License