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:

x² + 3x - 85 = 3x - 4
x² + 3x - 85 + 4 = 3x
x² + 3x - 3x - 81 = 0
x² - 81 = 0

Next, factor the quadratic equation:

x² - 81 = 0
(x - 9)(x + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x - 9) or (x + 9) must equal zero:

If (x - 9) = 0, x must equal 9
If (x + 9) = 0, x must equal -9

So the solution is that x = 9 or -9

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.

5a⁵ - 6a⁵ = -1a⁵

The volume of a cube is height x length x width:

v = h x l x w
v = 5 x 4 x 8
v = 160

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 2 + 8 + 5 + 9
p = 24

A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).