Sami was asked to solve the following system of equations using substitution. y=6x -4
y=2x

Here is the work that sami did:

2x = 6x -4
8x = -4
x = -0.5

And then to find y: y= 2 (-0.5) = -1

so Sami's answer for the point of intersection was (-0.5, -1).

Clearly state Sami's one error and then give the correct ordered pair for where the lines cross.

see explanation

Step-by-step explanation:

Sami's error is in the second line of working

2x = 6x - 4  ← correct substitution ( subtract 6x from both sides, Sami has added 6x )

- 4x = - 4 ← correct second line ( divide both sides by - 4 )

x = 1

Substitute x = 1 into either of the 2 equations and evaluate for y

Substituting into the second equation

y = 2x = 2(1) = 2

solution is (1, 2 )

1. perpendicular

2. parallel

3. perpendicular

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