Assuming x represents the length of the first side.
Use Pythagorean theorem to solve: a^2 + b^2 = c^2
Solve the quadratic equation using the quadratic formula.
At the end, you will get side lengths of #(-14 ± 34) / 4, or -12 and 5
SInce a negative triangle length is impossible, 5 is the value of x and 5 + 7 is the value of x + 7, which makes 12.
The formula for area of a right triangle is A = B H/2
After doing your work you should get. 30cm^2