7points!

i'm learning about equations with square roots & cube roots in 8th grade math. (image included)

my main question is what is this ± symbol?

It is the plus minus sign. It means to do the addition and subtraction.

Examples:

10 ± 7 = 17 and 3

15 ± 5 = 20 and 10

100 ± 90 = 190 and 10

It is generally used to indicate a possibility of two outcomes. A negative or positive outcome.