What is 14 equals 2 plus r-21?

Answer 1

In these types of questions, you have to try to isolate the unknown variable.

14 = 2 + r - 21.

Remember whenever you move ANYTHING over the equals sign, you have to make its sign opposite. Since the r is positive, and we are moving it over the equals sign we have to make it a negative sign. When we move the 14 over, it is currently positive so we make it into a negative.

-r = -14 + 2 - 21

-r = -12 - 21

-r = -43

(Eliminate the negative sign)

r = 43.