Consider the these two linear equations: 10x + 5y = 90
y = ax + 18
What value of a will make the two lines parallel?

  a = -2

Step-by-step explanation:

The first equation can be rewritten in slope-intercept form:

  5y = -10x +90

  y = -2x +18

The value a=-2 will make the second line identical to the first.

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560