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

-9b + z = 5
z = 5 + 9b

then substitute the result (5 - -9b) into the second equation:

-9b - 9(5 + 9b) = 9
-9b + (-9 x 5) + (-9 x 9b) = 9
-9b - 45 - 81b = 9
-9b - 81b = 9 + 45
-90b = 54
b = \( \frac{54}{-90} \)
b = -\(\frac{3}{5}\)

The area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 7 x 8
a = 56

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with w° = 37, the value of y° is 143.

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 9 x 3) + (2 x 3 x 3) + (2 x 9 x 3)
sa = (54) + (18) + (54)
sa = 126