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 + 2a - 32 = 5a - 4
a² + 2a - 32 + 4 = 5a
a² + 2a - 5a - 28 = 0
a² - 3a - 28 = 0

Next, factor the quadratic equation:

a² - 3a - 28 = 0
(a + 4)(a - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a + 4) or (a - 7) must equal zero:

If (a + 4) = 0, a must equal -4
If (a - 7) = 0, a must equal 7

So the solution is that a = -4 or 7

An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:

d° = b° + c°

To find angle c, remember that the sum of the interior angles of a triangle is 180°:

180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 20° - 22° = 138°

So, d° = 22° + 138° = 160°

A shortcut to get this answer is to remember that angles around a line add up to 180°:

a° + d° = 180°
d° = 180° - a°
d° = 180° - 20° = 160°

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.

5a⁶ - 2a⁶ = 3a⁶

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.

A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.