Respuesta :

nottinghama669

Answer:

a= 12

b= 9

I hope this helps

thebecks

Answer:

a=12

b=9

Step-by-step explanation:

b=0.75a

a+b=21

a+0.75a=21

1.75a=21

a=12

a+b=21

12+b=21

b=9

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