Please help and thank you

Answer:
[tex]b_{1}=\frac{2A}{h}-b_{2}[/tex]
Step-by-step explanation:
Given: [tex]A=\frac{1}{2}(b_{1} +b_{2})h[/tex]
We need to completely isolate [tex]b_{1}[/tex] to solve.
[tex]A=\frac{1}{2}(b_{1} +b_{2})h[/tex]
[tex]A=(\frac{1}{2}b_{1} +\frac{1}{2} b_{2})h[/tex]
[tex]A=\frac{1}{2}b_{1} h+\frac{1}{2}b_{2}h[/tex]
[tex]-\frac{1}{2}b_{1}h+A=\frac{1}{2}b_{2}h[/tex]
[tex]-\frac{1}{2}b_{1}h=-A+\frac{1}{2}b_{2}h[/tex]
[tex]-\frac{1}{2}b_{1}=\frac{-A}{h}+\frac{1}{2}b_{2}[/tex]
Finally, multiply both sides by -2 to completely isolate [tex]b_{1}[/tex].
[tex]b_{1}=\frac{2A}{h}-b_{2}[/tex]
The right option is D
See the image