Question

1 of 3

F
Find the equation of the line that passes through (1,3) and is perpendicular to
y = 2x + 3.
Leave your answer in the form y = mx + c

Answer 1

y = -1/2x + 3.5

Explanation:

The gradients of perpendicular lines multiply to make -1. The gradient of the line given is 2, so 2 multiplied by something gives us -1. 2 × -1/2 = -1. The gradient of the perpendicular line is -1/2

y = -1/2x + c

Now we can substitute x = 1 and y = 3 into the equation:

• 3 = -1/2(1) + c
• 3 = -1/2 + c
• c = 3 + 1/2
• c = 3 1/2 or 3.5 or 7/2

The equation of the line is y = -1/2x + 3.5

Hope this helps!