Question

What is the equation of the line that is perpendicular to -2/5x-7 and passes through (4,-1)?

Answer 1

Step-by-step explanation:

maybe this is not the full expression, as you wrote the line equation in a funny way.

I understand the following :

the line is

y = (-2/5)×x - 7

perpendicular means crossing at a right angle (90 degrees).

the slope of the original line is -2/5.

as in every line equation, the slope is the factor of x. and it expresses the ratio y/x indicating the amount of units y is changing, when x changes a certain amount of units (e.g. when going from one point on the line to another).

the perpendicular slope turns the original y/x ratio upside-down, and also flips the sign.

so, it is 5/2.

the equation for the perpendicular line looks like

y = (5/2)×x + b

now what is b ?

for this we use the specified point on the line : (4, -1)

and we put these values as x and y into the equation :

-1 = (5/2)×4 + b = 5×2 + b = 10 + b

b = -11

and so, the full equation of the perpendicular line is

y = (5/2)×x - 11