Question

What is the equation of a line that passes through the point (1, 3) and is parallel to a line with a slope of -2? A. y = -2x + 3 B. y = -2x + 5 C. y = 2x + 3 D. y = 2x + 5

Answer 1

The slope-intercept form:

y = mx + b

m - slope

b - y-intercept

Parallel lines have the same slope. Therefore m = -2.

We have the equation of a line:

y = -2x + b

Put the coordinates of the point (1, 3) to the equation of a line:

3 = -2(1) + b

3 = -2 + b add 2 to both sides

5 = b → b = 5

Answer: B. y = -2x + 5

Answer 2

The answer is B(y=-2x+5)
It's better explained by that if a line passes through a point, the point must satisfy the equation of the line
i.e y=-2x+5 and (x,y)=(1,3)
substituting values for x and y in the line equation.
3=-2(1)+5
3=3.