First you had to switch sides of equation.

Then you divide by two from both sides of equation form.

Simplify.

Next, subtract by i from both sides of equation form.

Finally, simplify by equation.

Final answer: 
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie
The answer would be $25.22 the way to do this would be to divide 7.76 by 4 and then you would multiply that answer by 13 so it would be the 4th answer
Simplifying
8a + 12b = 92
Solving
8a + 12b = 92
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '-12b' to each side of the equation.
8a + 12b + -12b = 92 + -12b
Combine like terms: 12b + -12b = 0
8a + 0 = 92 + -12b
8a = 92 + -12b
Divide each side by '8'.
a = 11.5 + -1.5b
Simplifying
a = 11.5 + -1.5b
Original area of triangle divided by 10 is the answer to your question.