#### Question

# Need help on 3 math problems?

16. Is the line through points P(–8, –10) and Q(–5, –12) perpendicular to the line through points R(9, –6) and S(17, –5)? Explain. (1 point)

Yes, their slopes are different.

No, their slopes are not opposite reciprocals.

No, their slopes are not the same.

Yes, their slopes have the same number in them.

18. What is an equation for the line that passes through points (8, –3) and (9, 10)? (1 point)

(y + 3) = –13(x – 8)

(y + 3) = 13(x – 8)

(y – 3) = –13(x + 8)

(y – 3) = 13(x + 8)

21.Is the line through points P(–7, 2) and Q(7, –6) parallel to the line through points R(–1, –5) and S(–3, –1)? Explain. (1 point)

No; one line has zero slope, the other has no slope.

Yes; the lines are both vertical.

Yes; the lines have equal slopes.

No; the lines have unequal slopes.

#### Answer

slope = difference in y's over difference in x's

16)

(-10-(-12))/(-8-(-5))= (-2)/(-3)=2/3

(-6-(-5))/(9-17)=(-1)/(-8)=1/8

their slopes are not the same.

18)

slope = (-3-10)/(8-9)= -13/-1= 13

(y-(-3))= 13(x-8)

(y+3)= 13(x-8)

21)

(2-(-6))/(-7-7)= 8/-14= 4/7

(-5-(-1))/(-1-(-3))= -4/2=-2

different slopes