To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so add the coefficients and retain the base and exponent:

-2x⁴ + 1x⁴
(-2 + 1)x⁴
-x⁴

A factor is a positive integer that divides evenly into a given number. For example, the factors of 8 are 1, 2, 4, and 8.

To convert a negative exponent to a positive exponent, calculate the positive exponent then take the reciprocal.

To add these radicals together their radicands must be the same:

8\( \sqrt{63} \) + 7\( \sqrt{7} \)
8\( \sqrt{9 \times 7} \) + 7\( \sqrt{7} \)
8\( \sqrt{3^2 \times 7} \) + 7\( \sqrt{7} \)
(8)(3)\( \sqrt{7} \) + 7\( \sqrt{7} \)
24\( \sqrt{7} \) + 7\( \sqrt{7} \)

Now that the radicands are identical, you can add them together:

The factors of 36 are [1, 2, 3, 4, 6, 9, 12, 18, 36] and the factors of 68 are [1, 2, 4, 17, 34, 68]. They share 3 factors [1, 2, 4] making 4 the greatest factor 36 and 68 have in common.