To do this, you must use the order of operations.
3·2=6
6+4=10
Now to solve (-)x.
Since -x comes in front of 4, you must make your equation:
-x+10
Nothing is written for x, so now, you have the answer.
-x+10
Answer:

Step-by-step explanation:

Answer:
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
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