Answer:
b₂ = (2A)/h -b₁
Step-by-step explanation:
Forget the fact that the characters are letters and not numbers. The same rules of math apply.
In general, you "undo" what is done to the variable you're interested in. If you consider the order of operations, you see that b₂ is ...
- added to b₁
- the sum multiplied by h/2
You "undo" these in reverse order.
Undo the multiplication by h/2 by multiplying both sides of the equation by 2/h. Undo the addition by adding the opposite.
[tex]A=\dfrac{h}{2}(b_1+b_2)\qquad\text{given}\\\\\dfrac{2}{h}A=b_1+b_2\qquad\text{multiply by $2/h$}\\\\\dfrac{2A}{h}-b_1=b_2\qquad\text{subtract $b_1$}\\\\\boxed{b_2=\dfrac{2A}{h}-b_1}[/tex]
