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.

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 2 + 5 + 8 + 7
p = 22

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 7cm + 11cm + 10cm = 28cm

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.

8a + 2a = 10a

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:

z² + z - 14 = -5z + 2
z² + z - 14 - 2 = -5z
z² + z + 5z - 16 = 0
z² + 6z - 16 = 0

Next, factor the quadratic equation:

z² + 6z - 16 = 0
(z - 2)(z + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z - 2) or (z + 8) must equal zero:

If (z - 2) = 0, z must equal 2
If (z + 8) = 0, z must equal -8

So the solution is that z = 2 or -8