b=9,a=12
Step-by-step explanation:
I solved by substitution:
b = 3/4a  ---> plug this into the other equation
a + b = 21  is now   a + 3/4a = 21
Reduce: 7/4a = 21
a = 12
Now solve for b:
b=3/4a is now b=3/4(12)
b=9
b. x + 1
step-by-step explanation:
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