Answer:
2A/w - b =c
Step-by-step explanation:
A =1/2w(b+c)
multiply each side by 2
2A = 2* 1/2 w * (b+c)
2A = w * (b+c)
divide each side by w
2A /w= w/w * (b+c)
2A/w = b+c
subtract b