Question

Solve b=3/4 a
a+b=21

Answer 1

20.25

Explanation:

21-3/4=20.25

Answer 2

Explanation:

a+b=21

a=21-b

b=3/4*a

b=3/4*(21-b)

b=3(21-b)/4

b=63-3b/4

4*b=63-3b

4b+3b=63

7b=63

b=63/7

b=9