The answer is algebraic work. Algebra is a based math is the piece of arithmetic in which letters and other general images are utilized to speak to numbers and amounts in formulae and conditions.
I hope the answer will help you. Feel free to ask more questions.
Answer:

Step-by-step explanation:
see the attached figure , to better understand the problem
we have

where
A(b) ---> is the trapezoid's area
b ---> is the other base value
Solve the equation for b
That means ----> isolate the variable b
Divide 12 by 2 right side

Divide by 6 both sides

subtract 9 both sides

Rewrite

Convert to function notation

Answer:
No, You can't. You have to make their denominators equal!

Step-by-step explanation:
So first, you make their denominators equal!

Multiplying both the numerator and denominator with the same number results in the same fraction, just un-simplified
So, we input it!

There you go!
Hope you get better at math!(gets wayyyyyyyyyyy...y more complicated later)
Hope this helps!
See Ya!
P.S. Stay Safe!