Which of the following statements are true? select all that apply

a. < 2 and < 3 form a linear pair
b. < 1 and < 4 are supplementary angles
c. m< 1 + m< 2 + m< 3 = 180
d. m< 3 + m< 4 = m< +m < 2
e. < 1 and < 4 are vertical angles

What values of x satisfy the inequality x^2-9x< 0? how is your answer shown on the graph?

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36

Write as a product: ac^2–ad+c^3–cd–bc^2+bd