I hope this helps you
take both of sides paranthesis square
(2a+7b)^2=(11)^2
4a^2+2.4a.7b+49b^2=121
4a^2+49b^2+56.2=121
4a^2+49b^2=9

The mistake is in Step 1. The solver should have also squared
when squaring the other side of the equation.
<h3>Correctly solving</h3>

Answer:
5 cups
The Commutative Property of Addition
Step-by-step explanation:
They have a common denominator of 12
21/12+6/12+20/12+4/12+3/12+6/12=60/12=5 cups
or you could group ingredients with the same denominators
7/4+1/4+1/2+1/2+5/3+1/3=
8/4+2/2+6/3=
2+1+2=5
The Commutative Property of Addition says the order of the numbers doesn’t change the outcome.
Answer:
25% or 30L
Step-by-step explanation:
100% is 120L, we know 75% is acid, we need the other 25% to make the 100%. 25% of 120 is 30, so 30 liters is pure acid