A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

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

-7a + x = 6
x = 6 + 7a

then substitute the result (6 - -7a) into the second equation:

5a - 6(6 + 7a) = -9
5a + (-6 x 6) + (-6 x 7a) = -9
5a - 36 - 42a = -9
5a - 42a = -9 + 36
-37a = 27
a = \( \frac{27}{-37} \)
a = -\(\frac{27}{37}\)

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the > sign and the answer on the other.

6x - 1 > 4 - 8x
6x > 4 - 8x + 1
6x + 8x > 4 + 1
14x > 5
x > \( \frac{5}{14} \)
x > \(\frac{5}{14}\)

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).