## Trigonometry (10th Edition)

1. Once two angles form straight line, you know they must add up to be $180^{\circ}$. Don't be thrown by the coefficients being negative; it just means that we should expect a negative number of x. (-4x) + (-14x) = 180 -18x = 180 x = -10 2. Insert the value of x to find the unknown angles (-4)(-10) = 40° (-14)(-10) = 140°