Question

Solve the system of linear equations by substitutionb) 3x - 4y = 102y + 4x = 6

Answer 1

3x - 4y = 10 (eq. 1)

2y + 4x = 6 (eq. 2)

Isolating y from the second equation:

`\begin{gathered} 2y=6-4x \\ y=(6-4x)/(2) \\ y=(6)/(2)-(4x)/(2) \\ y=3-2x \end{gathered}`

Substituting this equation into the first equation:

3x - 4(3 - 2x) = 10

3x - 4(3) + 4(2x) = 10

3x - 12 + 8x = 10

11x - 12 = 10

11x = 10 + 12

11x = 22

x = 22/11

x = 2

Then,

y = 3 - 2x

y = 3 - 2(2)

y = 3 - 4

y = -1