Question 503267

{{{(5x^2+9)+(2x^2-8x+3)}}} Start with the given expression


{{{5x^2+9+2x^2-8x+3}}} Remove unneeded parenthesis


{{{(5x^2+2x^2)-8x+(9+3)}}} Group like terms


{{{7x^2-8x+12}}} Combine like terms


So {{{(5x^2+9)+(2x^2-8x+3) = 7x^2-8x+12}}}