-7+(-3) equals -10 so maybe that might help you
Writing equivalent equations help you solve system of equations because it sets it up for being broken down part by part.
Given that,
Radius of the circle, r = 8.91 cm
Angle, 
To find,
The area of minor sector.
Solution,
The formula for the area of minor sector is given by the formula as follows :

So, the area of the shaded sector is
.