Use a number line to multiply a 2 digit number by 20

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

Betty correctly answers 30 questions on your math test there are 40 questions on the test what percent of the questions did she answered incorrectly

40 points which is the equation of a line perpendicular to the line with the equation: y = 1/4x + 2 a : y = -4x - 7 b : y = 4x + 2 c : y = 1/4x - 1/2 d : y = -1/4x + 3