Question

3. What is the solution point of the system -7% - 4y= 4 and 3% + 9y=-920 (0,1)O (1,0)0 (-1,-1)O 0,-1)0 (-1,0)

Answer 1

The given equations are

- 7x - 4y = 4

3x + 9y = - 9

We would solve both equations simultaneously. We would apply the method of elimination. To eliminate y, we would multiply the first equation by 9 and the second equation by 4. The new equations would be

- 63x - 36y = 36

12x + 36y = - 36

Adding both equations, we have

- 63x + 12x - 36y + 36y = 36 - 36

- 51x = 0

Dividing both sides of the equation by - 51, we have

- 51x/- 51 = 0/- 51

x = 0

Substituting x = 0 into - 7x - 4y = 4, we have

- 7 * 0 - 4y = 4

0 - 4y = 4

- 4y = 4

Dividing both sides of the equation by - 4, we have

- 4y/- 4 = 4/- 4

y = - 1

The correct option is (0, - 1)