subtracting 9.1 - 12.9 is -3.8
We want to calculate the following

Using the properties of exponents, we have that

So we have

So, if factor 10^-4 on the right side, we have

Note that

Then,

So we have that
Answer:
it depends on the choices
Step-by-step explanation:
To solve a system of linear equations graphically we graph both equations in the same coordinate system. The solution to the system will be in the point where the two lines intersect. The two lines intersect in (-3, -4) which is the solution to this system of equations