Question

if 2a=3b and 4a+b=21, then b=
A 1
B 3
C 4
D 7

Answer 1

Answer:

2(2a)+b=21. 2(3b)+b=21 . 6b+b=21. 7b=21. b=3

Answer 2

Answer:

B 3

Step-by-step explanation:

2a=3b

a=3b/2

4a+b=21

4(3b/2)+b=21

2(3b)+b=21

6b+b=21

7b=21

b=21/7

b=3