Question

Add the following polynomials, then place the answer in the proper location on the grid. Write the answer in descending powers of x. Find the sum of (5x3 + 3x2 - 5x + 4) and (8x3 -5x2 + 8x + 9).

Answer 1

ANSWER
$13 {x}^{3} - 2 {x}^{2} + 3x + 13$

EXPLANATION

The first polynomial is
$5 {x}^{3} + 3 {x}^{2} - 5x + 4$


The second polynomial is
$8 {x}^{3} - 5 {x}^{2} + 8x + 9$


If we add the two polynomials we obtain,



$(5 {x}^{3} + 3 {x}^{2} - 5x + 4) + (8 {x}^{3} - 5 {x}^{2} + 8x + 9)$


Next we group like terms to obtain,


$5 {x}^{3} + 8 {x}^{3}+ 3 {x}^{2} -5 {x}^{2} - 5x + 8x + 9 + 4$



We simplify the to obtain,


$13{x}^{3} -2{x}^{2} + 3x + 13$

This is the sum of the two polynomials in descending powers of
$x$


Descending means from the highest power to the least.