Tell which equation you would use to isolate a variable in order to solve the system using substitution. explain your reasoning.

2x + y=-10
3x-y=0

Last year, a state university received 3,560 applications from boys. of those applications, 35 percent were from boys who lived in other states. part a)how many applications did the university receive from boys who lived in other states? part b)applications to the university from boys represented 40percent of all applications. how many applications did the university receive in all? i don't how to do part b so me and plz tell how you got your answer

Plz a. s. a. p.the table shows the number of male and female contestants who did not win a prize. what is the probability that a randomly selected contestant won a prize, given that the contestant was female? write the probability as a percent. round to the neares tenth, if needed.

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2