If and , then find the value of .
- A9
- B1
- C-9
- D-1
Solution & Step-by-step Explanation
We are given a system of two linear equations: Multiply equation (2) by 2 to match the coefficients of :
Add equation (1) and equation (3):
Substitute back into equation (2):
Now evaluate the required expression :
Add equation (1) and equation (3):
Substitute back into equation (2):
Now evaluate the required expression :