The last one 7(30)-7(7) because if you do it then it is 7(23) which doesn’t make sense because it is 27 we need to find
Given:
The figure of triangle ABC.
The area of the triangle ABC is D.

To find:
The value of m and n in the given expression.
Solution:
Let h be the height of the triangle ABC.
Area of a triangle is:

Where, b is the base and h is the height of the triangle.

The area of the triangle ABC is D.


...(i)
In a right angle triangle,


[Using (i)]
...(ii)
We have,
...(iii)
On comparing (ii) and (iii), we get


Therefore, the required values are
.
I am not sure i am in 7th grade but i prefer you to use the app called photomath
You would subtract 6 from both sides in order to get m by itself. When you do this you get m=-10