Answer:
[tex]b_{2} = \frac{2A}{h} - b_{1}\\[/tex]
Step-by-step explanation:
[tex]A = \frac{1}{2} h(b_{1} +b_{2})\\2A = h(b_{1} +b_{2})\\\frac{2A}{h} = b_{1} +b_{2}\\\frac{2A}{h} - b_{1} = b_{2}\\[/tex]
