### Home > AC > Chapter 7 > Lesson 7.3.4 > Problem 7-114

7-114.

Using *y* = *mx* + *b*, substitute the values of *m*, *y*, and *x* and solve for *b*.

Solve for *b* and rewrite the equation substituting *m* and *b* back into their original positions.

A horizontal line has zero slope. Therefore, simply substitute the values for *x* and *y* into the equation and solve for *b*.

Then, rewrite the equation with *m* and *b* substituted back into their original equations.

*y* = −11

See parts (a) and (b) to solve. Remember that perpendicular lines have opposite reciprocal slopes.