Question

line n passes through the points (-3, -7.5) and (2, -5). tahlia determined that the equation of line n is y = 0.5x. explain the error tahlia made while determining her equation. be sure to include the correct equation in your explanation​

Answer 1

Tahlia was correct in remembering that you can find the slope of a line using the slope formula.

She was also correct that the slope is 0.5.

However, if you use the slope-intercept formula y = mx + b, you still have to find b (the y-intercept) by plugging in one of the two points and the slope.

So, if we plug in the first point and the slope into the line, we can find b and thus the full equation of the line:

`-7.5=0.5(-3)+b\\-7.5=-1.5+b\\b=-6\\\\y=0.5x-6`