# Please explain/show work: perpendicular lines,....... very confused?

L passes (2,2) and perpendicular y=3x+7

L passes (-1,-2) and perpendcular 2y-3x=12

Relevance

If L is perpendiculat to y = 3x + 7, it means the slope of L is a negative reciprocal of the slope of y = 3x + 7.

The slope of y = 3x + 7 is 3, so the slope of L must is m = -1/3

We are given a point (2, 2) with slope m = -1/3. Use the point-slope formula:

y - 2 = -1/3(x - 2)

y - 2 = (-1/3)x + 2/3

y = (-1/3)x + 2/3 + 2

y = (-1/3)x + 8/3

For the second one, you need to find the slope of 2y - 3x = 12. To do this, solve for y.

2y - 3x = 12

2y = 3x + 12

y = (3/2)x + 6

So, L will have the slope m = -2/3. It passes through (-1, -2), so we use the point-slope formula again.

y - - 2 = -2/3(x - - 1)

y + 2 = -2/3(x + 1)

y + 2 = (-2/3)x - 2/3

y = (-2/3)x - 2/3 - 2

y = (-2/3)x - 8/3

• Anonymous
8 years ago

m is opposite and recipocal so 3 is -1/3 than solve for b. As in 2= -1/3(2)+b. The answer then is y=-1/3x+1.33333......with the little slash over the 3.

2) so get that into y=mx+b form. y=3/2x+6. the opposite recipocal is -2/3. solve--------- -2=-2/3(-1)+b

you then have the answer of y=-2/3x=2.6666666......with the little slash over the 6

Source(s): my head, pencil, and paper
• Anonymous
8 years ago

more specific?