A trapezoid is a quadrilateral with one set of parallel sides.

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

y² - 5y + 4 = 0
(y - 1)(y - 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 1) or (y - 4) must equal zero:

If (y - 1) = 0, y must equal 1
If (y - 4) = 0, y must equal 4

So the solution is that y = 1 or 4

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.

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 9 x 4 = \( \frac{36}{2} \) = 18

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.

7a + 7a = 14a