Question

Find an equation for the line perpendicular to 4x+12y=72 and goes through the point (-9,6)

Answer 1

Answer:

Step-by-step explanation:

Given the equation

4x+12y=72

The equation of a line can written as

y=mx+c

Where m is the slope

And c is the intercept on y axis

Then, we need to write the equation given in the form of equation of a line (y=mx+c), by making y subject of the formula

4x+12y=72

12y=-4x+72

Divide through by 12

y=-4x/12 + 72/12

y=-⅓x+6

Then, comparing with equation of a line shows that

m=-⅓ and c=6

So we need to get another linen that is perpendicular to this line and passes through the point (-9,6)

The slope of the line perpendicular to another line is given as

m1=-1/m2

Then, m1=-1÷-⅓

Then, the slope of the perpendicular line is 3

Then, m=3

So apply this to equation of the line

y=mx+c

Then, y=3x+c

So to know c, we will insert the point given(-9,6), x=-9 and y=6

y=3x+c

6=3(-9)+c

6=-27+c

Then, c=6+27

c=33

Then, the equation of line becomes

y=3x+33