4 is missing I assume. But I could be wrong
Area = 140
16 x 8 = 128
16-12 = 4
(6x4)/2 = 12
128 + 12= 140
⇒

is a improper fraction.

as a mixed number would be 4

⇒10 x 4 = 40
⇒40 + 9 = 49

= 4
⇒ANSWER = 4
The Answer is 2
34.989.I used a physics book
The answer is D because you can multiply the second equation by -4