I feel so idiotic right now, pls help

Which ordered pair (c, d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

Mr. and mrs. wallace have decided to buy a car for $21,600. they finance $15,000 of it with a 5-year auto loan at 2.9% arp. what will be their monthly payment be? a. $268.20 b. $268.86 c. $269.54 d. $387.16 i need !

Secant ac and bd intersect at point e inside f what is the measure of aed if measurements cd equals 30 a b is 50 and cb is 170