Answer:
b=3
Step-by-step explanation:
2a=3b and 4a+b=21,
Multiply the first equation by 2
2(2a) = 2*3b
4a = 6b
Substitute this into the second equation
4a+b = 21
Replace 4a with 6b
6b+b = 21
Combine like terms
7b = 21
Divide each side by 7
7b/7 = 21/7
b = 3
