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).

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

y² - 5y - 24 = 0
(y + 3)(y - 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 3) or (y - 8) must equal zero:

If (y + 3) = 0, y must equal -3
If (y - 8) = 0, y must equal 8

So the solution is that y = -3 or 8

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.

5a - 7a = -2a

To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

-4b(b - y)
-4(4)(4 + 1)
-4(4)(5)
(-16)(5)
-80

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD