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 equal sign and the answer on the other.

-x - 7 = 9 - 7x
-x = 9 - 7x + 7
-x + 7x = 9 + 7
6x = 16
x = \( \frac{16}{6} \)
x = 2\(\frac{2}{3}\)

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 x° = 155, the value of c° is 25.

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses.

To solve this equation, isolate the variable for which you are solving (c) on one side of the equation and put everything else on the other side.

6c - 7x = c + 4x - 9
6c = c + 4x - 9 + 7x
6c - c = 4x - 9 + 7x
5c = 11x - 9
c = \( \frac{11x - 9}{5} \)
c = \( \frac{11x}{5} \) + \( \frac{-9}{5} \)
c = 2\(\frac{1}{5}\)x - 1\(\frac{4}{5}\)