B is the correct answer
hope this helps
Where you take a word problem and turn it into an equation
first we need to get rid of the ( ) so that we can see what the question really says
(3x³-5x² - 7+ 4x4) + (9x4 - 10x² - 5x³ + 3)
= 3x³-5x²-7+4x⁴+9x⁴-10x²-5x³+3
now all we need to do is add up the numbers with the same x's
<em>3x³</em>-5x²-7<u>+4x⁴+9x⁴</u>-10x²<em>-5x³</em>+3
= 13x⁴-2x³-15x²-4
