Simplify 8 - (-5) - 4(-7). -63 -15 41 68

Use the elimination method to find the solution to the system of equations. 2x - 3y = -9 -x + 3y = 6

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of

Varies inversely with x. if y=8.5 when x=-1 find x when y=-1