Question 152629
The key is to group like terms and perform operations on them.
Group the {{{x^2}}} terms, the {{{x}}} terms and the constants.
Use the distributive properties and watch the signs.
{{{(4x^3+x^2-3) - (-9x^3+5x^2-6)=(4x^3-(-9x^3))+(x^2-5x^2)+(-3-(-6))}}}
{{{(4x^3+x^2-3) - (-9x^3+5x^2-6)=(4x^3+9x^3)+(x^2-5x^2)+(-3+6)}}}
{{{(4x^3+x^2-3) - (-9x^3+5x^2-6)=(13x^3)+(-4x^2)+(3)}}}
{{{(4x^3+x^2-3) - (-9x^3+5x^2-6)=13x^3-4x^2+3}}}