3(a + b) and 3a + b - NOT EQUIVALENT because
3(a + b) = 3a + 3b
<em>used distributive property a(b + c) = ab + ac</em>
4(x + 2y) and 8y + 4x - EQUIVALENT because
4(x + 2y) = (4)(x) + (4)(2y) = 4x + 8y = 8y + 4x
<em>used distributive property a(b + c) = ab + ac</em>
<em>and commutative property a + b = b + a</em>
Anything with || around it is a whole value. It’s always a positive. For example, |-56|=56. Now, if the negative was on the outside, it would be a negative like so; -|10| =-10
Because Z is directly proportional to X and inversely proportional to Y, therefore

where k = constant.
When X = 15 and Y = 9, Z = 5. Therefore
k(15/9) = 5
k = 5*(9/15) = 3
That is,

When X = 23, and Y = 14, obtain
Z = (3*23)/14 = 4.9286
Answer: Z = 4.929 (nearest thousandth)