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.

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(5a)(7ab) + (4a²)(4b)
(5 x 7)(a x a x b) + (4 x 4)(a² x b)
(35)(a¹⁺¹ x b) + (16)(a²b)
35a²b + 16a²b
51a²b

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 - 13x + 17 = -3x + 1
x² - 13x + 17 - 1 = -3x
x² - 13x + 3x + 16 = 0
x² - 10x + 16 = 0

Next, factor the quadratic equation:

x² - 10x + 16 = 0
(x - 2)(x - 8) = 0

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

If (x - 2) = 0, x must equal 2
If (x - 8) = 0, x must equal 8

So the solution is that x = 2 or 8

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 69° - 61° = 50°

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.