The slope perpendicular to the one given is the opposite reciprocal. So the slope of the "new" line will be -1/5. Using y = mx + b and filling in 3 for y, -10 for x and the slope, m, of -1/5 will help you solve for b. Then use that b to write the new equation. 3= -1/5(-10) + b and b = 1. Your equation, then, is y = -1/5x + 1
