Respuesta :

lydiahon

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

Answer:

a=12 b= 9

Step-by-step explanation:

did the quiz