Does someone know how to do this if you do can you please answer these questions thanks

Which of the following contains a variable?

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14

Recall that two angles are complementary if the sum of their measures is? 90°. find the measures of two complementary angles if one angle is twenty dash nine times the other angle.