Question

solve by elimination method x+y=7 3x+4y=27

Answer 1

Solve equation [2] for the variable y

[2] y = -2x - 7

// Plug this in for variable y in equation [1]

[1] 3x - 4•(-2x-7) = -27

[1] 11x = -55

// Solve equation [1] for the variable x

[1] 11x = - 55

[1] x = - 5

// By now we know this much :

x = -5

y = -2x-7

// Use the x value to solve for y

y = -2(-5)-7 = 3

Solution :

{x,y} = {-5,3}

:

Step-by-step explanation:

Answer 2

Answer:

// Solve equation [2] for the variable y

[2] y = -2x - 7

// Plug this in for variable y in equation [1]

[1] 3x - 4•(-2x-7) = -27

[1] 11x = -55

// Solve equation [1] for the variable x

[1] 11x = - 55

[1] x = - 5

// By now we know this much :

x = -5

y = -2x-7

// Use the x value to solve for y

y = -2(-5)-7 = 3