9.)
r = 42cosθ−3sinθ r(2cosθ−3sinθ) = 4 2rcosθ−3rsinθ = 4 2x−3y = 4 becausex=rcosθandy=rsinθ 2x = 4+3y 2x−4 = 3y 23x−43 = y y = 23x−43
This is the equation of a line with a slope of 23 and a y-intercept of −43 .
Check: https://www.desmos.com/calculator/7dq2bqym7k
(You can show or hide the second equation by clicking the gray circle to the left of it. )