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

a² + 3a - 40 = 0
(a - 5)(a + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a - 5) or (a + 8) must equal zero:

If (a - 5) = 0, a must equal 5
If (a + 8) = 0, a must equal -8

So the solution is that a = 5 or -8

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

2y - 7 < -1 + 6y
2y < -1 + 6y + 7
2y - 6y < -1 + 7
-4y < 6
y < \( \frac{6}{-4} \)
y < -1\(\frac{1}{2}\)

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.

7a⁹ + 2a⁹ = 9a⁹

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.

(9a)(7ab) + (9a²)(7b)
(9 x 7)(a x a x b) + (9 x 7)(a² x b)
(63)(a¹⁺¹ x b) + (63)(a²b)
63a²b + 63a²b
126a²b