# How do you simplify (20x^6 - 13x^5) - (-7x^6 + 7x^5 - 20x^3 - 4x^2)?

$= 20 {x}^{6} - 13 {x}^{5} + 7 {x}^{6} - 7 {x}^{5} + 20 {x}^{3} + 4 {x}^{2}$ ( the $-$ changes the signs of the numbers in the parenthesis )
$= 27 {x}^{6} - 20 {x}^{5} + 20 {x}^{3} + 4 {x}^{2}$
=(x²)*(27x^4-20x^3+20x+4) ( if you want to factor it )