Question

What is an equation of the line that passes through the point (-7,-6)(−7,−6) and is parallel to the line x-y=7x−y=7?

Answer 1

Answer:

y = x + 1

Step-by-step explanation:

The gradient of a line can be defined by the equation:

m (gradient) = (y1 – y2 ) ÷ (x1 – x2) ----> "1" and "2" should be in subscript

For (-7,-6) we use x2 and y2 (because this point can be anywhere along a line):

x2 = -7, y2 = -6

Plug these values into the formula above:

m = (y-(-6)) ÷ (x-(-7))

m = (y+6) ÷ (x+7)

At this stage, the equation can't be solved as there are two unknowns. Therefore, the gradient must be found another way. Two lines are parallel if they have the same gradient - in their y=mx+c equations, m will be equal.

x - y=7 is the line alluded to in the question. Rearranging this equation into the line equation format gives:

y = x-7 ---> The gradient (coefficient of x) is 1.

Therefore, the gradient of the other parallel line must also be 1.

This can be substituted into the previous equation to give:

1 = (y+6)÷(x+7)

x+7 = y+6

x+1 = y

Therefore, the answer is y=x+1