To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(5a)(5ab) + (4a²)(8b)
(5 x 5)(a x a x b) + (4 x 8)(a² x b)
(25)(a¹⁺¹ x b) + (32)(a²b)
25a²b + 32a²b
57a²b

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

2a² - 4a² = -2a²

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

a² + 4a + 3 = 0
(a + 1)(a + 3) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a + 1) or (a + 3) must equal zero:

If (a + 1) = 0, a must equal -1
If (a + 3) = 0, a must equal -3

So the solution is that a = -1 or -3