Question

How do you write the equation of a line passing through (-5, 2) and parallel to the line whose equation is y=-4x +3?

Answer 1

`y = -4x + 10`

Explanation:

We know that the slope of the line is 4 units down for every 1 unit to the right, and that the line intercepts the y axis at 3. A parallel line will have a different y intercept but the same slope, so we already know that the equation must be `y = -4x + b`, with b as the y intercept.

We also know that the line passes through point (-5,2). We can thus substitute x and y for -5 and 2 respectively, to find b.

`2 = (-4 * 2) + b`

Simplify the equation
`2 = -8 + b`

Add 8 to both sides
`10 = b`
`b = 10`

`y = -4x + 10`