Question

8. Identify the solution to the system of equations: 4x - y = 7-12x + 3y = -21

Answer 1

The given system of equations is

`4x-y=7\text{ take it as equation (1)}`
`-12x+3y=-21\text{ take it as equation (2).}`

Consider equation (1)

`4x-y=7`

Subtracting 4x from both sides, we get

`4x-y-4x=7-4x`

`-y=7-4x`

Multiply both sides by -1, we get

`-y(-1)=(-1)7-(-1)4x`

`y=4x-7`

Substituting y=4x-7 in equation (2), we get

`-12x+3(4x-7)=-21`

`-12x+3(4x-7)=-21`