Question

Tabitha is trying to find the equation of a line perpendicular to y = 1/2 x - 5 in slope-intercept form that passes through the point (2, -7) which of the following equations will she use

Y - (-7) = 1/2 (x - 2)

Y - 2 = 1/2 (x - (-7))

Y - (-7) = -2(x - 2))

Y - 2 = -2(x - (-7)

Answer 1

Answer: y - (-7) = -2(x-2)

Answer 2

To be perpendicular, the slopes must be negative reciprocals of one another, mathematically:

m1*m2=-1 our reference line has a slope of 1/2 so our perpendicular line must have a slope of:

m/2=-1

m=-2

The slope-intercept form of a line is y=mx+b so we have so far:

y=-2x+b, using point (2,-7) we can solve for b

-7=-2(2)+b

-7=-4+b

-3=b so our perpendicular line is:

y=-2x-3

If you MEANT what is the perpendicular line is POINT-SLOPE form then we know the slope is -2 and the point is (2,-7)...

POINT-SLOPE form is:

y-y1=m(x-x1), where m=slope and (x1,y1) is any point on the line then:

y--7=-2(x-2) (that would be the third one down in your choices)


...

"slope-intercept" form is: y=mx+b

"point-slope" form is: y-y1=m(x-x1)

"standard" from is: ax+by=c