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multiple choice: which line below is perpendicular to y=-2/3x+5?

A. 2x-3y=6 B. 2x+3y=6 C. 2x-3y=6 D. 3x+2y=6

User Ny
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1 Answer

5 votes

Answer:

actually : none of them do. your teacher made a mistake (of you mistyped her something).

I suspect somebody mistyped C (see below), and that should have been the correct answer.

Explanation:

the slope in a

y = ... form

is always the factor of x.

therefore, the slope of

y / (-2/3)x + 5

is

-2/3

a perpendicular slope turns the original slope ratio upside down and flips the sign.

in our case :

3/2

to check and compare we need to transform all the answer options into y = ... forms :

A.

2x - 3y = 6

-3y = -2x + 6

3y = 2x - 6

y = (2/3)x - 2

no, 2/3 is NOT the needed 3/2.

B.

2x + 3y = 6

3y = -2x + 6

y = (-2/3)x + 2

no, -2/3 is NOT the needed 3/2

C.

2x - 3y = 6

this is the same as A.

I assume it was meant to be 3x - 2y = 6.

then this would have been the correct answer.

but as it is written : no, like A.

D.

3x + 2y = 6

2y = -3x + 6

y = (-3/2)x + 3

no, -3/2 is NOT the needed 3/2

User Mukesh Joshi
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7.7k points