Question

A student writes the equation for a line that has a slope of -6 and passes through the point (2,-8).

y -(-8) = 6(x - 2)

y -(-8) = -6x + 12

y -(-8) + 8 = 6x + 12 + 8

y = -6x + 20

Explain why the work is not correct.

Answer 1

y = kx+m is the linear equation

k: the slope

m: where the line crosses the y-axis

which gives

Explanation:

y=-6x + m

insert the coordinates in the equation

-8 = -6 * 2 + m

-8 = -12 + m

m = -8 + 12

m = 4

--> ans: y = -6x + 4

Answer 2

The student should have simplified the equation to have y + 8 on the left.

Then, the student should have subtracted 8 from both sides of the equation.

The value of b should be 4, not 20.

Explanation:

Hope this helps!