I don't see a mistake. You solve in parentheses first, then you solve exponents. If the exponent is 0 in this context, the answer would be 0.
Answer:
20
Step-by-step explanation:
20+20=40
It would be: 567/18 = 31.5
So, she needs atleast 32 shelves....
To see how they are related, let us solve the two equations.
FIRST EQUATION



SECOND EQUATION



Hence the solutions to the two equations are ADDITIVE INVERSE of each other.
Answer:
first one with -1...21
Step-by-step explanation:
only one that follows quadratic formula format