The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 8 x 8) + (2 x 8 x 1) + (2 x 8 x 1)
sa = (128) + (16) + (16)
sa = 160

You need to find the value of b so solve the first equation in terms of x:

-7b + x = 2
x = 2 + 7b

then substitute the result (2 - -7b) into the second equation:

5b + 1(2 + 7b) = -8
5b + (1 x 2) + (1 x 7b) = -8
5b + 2 + 7b = -8
5b + 7b = -8 - 2
12b = -10
b = \( \frac{-10}{12} \)
b = -\(\frac{5}{6}\)

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.