Question

Solve using elimination|
-x - 2y = -1,
-2x - 2y = -10

{___, ____}

Answer 1

(-9, -4)

Firstly we will arrange the equations one after the other:

-2x - 2y = -10 -----(i)

-x - 2y = -1 ------(ii)

+ + + (We are eliminating by subtracting equations signs change)

x = -9 (value of x)

putting value of x in equation (i)

-x -2y = -1 i.e. -(-9) -2y = -1 i.e. -9 -2y= -1

which gives y = -4.

Answer 2

(9, -4)

Explanation:

The question says to solve using elimination. Subtract the 2nd equation from the 1st equation, thus eliminating the y term completely. You will be left with an equation in terms of x, which you will then solve for and substitute into one of the original equations to calculate y.

-x - 2y = -1

- (-2x - 2y = -10)
_____________

Distribute the negative sign throughout the entire equation to reduce chance of making mistakes.

-x - 2y = -1

+ (2x + 2y = 10)
______________

x + 0y = 9

x = 9

Now substitute this value into the first equation to solve for y.

-(9) - 2y = -1

-9 - 2y = -1

-2y = 8

y = -4

So the solution of the equation is (9, -4).