The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

a² - 5a - 20 = -3a - 5
a² - 5a - 20 + 5 = -3a
a² - 5a + 3a - 15 = 0
a² - 2a - 15 = 0

Next, factor the quadratic equation:

a² - 2a - 15 = 0
(a + 3)(a - 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a + 3) or (a - 5) must equal zero:

If (a + 3) = 0, a must equal -3
If (a - 5) = 0, a must equal 5

So the solution is that a = -3 or 5

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) + (9a²)(7b)
(5 x 5)(a x a x b) + (9 x 7)(a² x b)
(25)(a¹⁺¹ x b) + (63)(a²b)
25a²b + 63a²b
88a²b

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

To solve this equation, isolate the variable for which you are solving (c) on one side of the equation and put everything else on the other side.

3c + x = 5c + 3x - 3
3c = 5c + 3x - 3 - x
3c - 5c = 3x - 3 - x
-2c = 2x - 3
c = \( \frac{2x - 3}{-2} \)
c = \( \frac{2x}{-2} \) + \( \frac{-3}{-2} \)
c = -x + 1\(\frac{1}{2}\)

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).