Imagine two planets, Planet Earth and Planet Mars in our Solar System. Imagine planets the same size, but Planet Earth has more mass than Planet Mars. Suppose two identical space vehicles with equal mass land on each planet. Which of the following statements is true?

as many times as you want

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

b is the answer and if you need further with anything message me