Question

write an equation to match each description.

1) a snowball is 8 cm across and melting so that its diameter is decreasing at a steady rate of 0.2 cm/min. write an equation for d(t), the length of the snowball's diameter at time t.
answer: d(t)=8-0.2t

2) horizontal line through (-1,3)
answer: y=3

3) line through (2,5) that is parallel to y=2x+7
answer: y-5=?(x-2)

4) line through (-2,4) that is perpendicular to y=1

are my answers right? and please help me on number 3 and 4.

Answer 1

3) slope = m = 2
5 = 2*2 + b
b = 1
so
y = 2 x + 1

4) slope = m = -1/1 = -1
so y = -x + b
4 = 2 + b
b = 2
so
y = -x + 2