Does anyone understand number 4.?

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

Which of the following can be used to explain a statement in a geometric proof?

What is the measure of sty in oo below? 130 310 230 50