Which one of the following equations is equivalent to 3x - 12 = -9 ? A= 2x = 4

B= x - 5 = -6

C= x + 3 = x - 1

D= 7x - 3 = 4

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