Answer:
Step-by-step explanation:
27 - 1.5x ≤ 36
54 - 3x ≤ 72
54 - 72 ≤3x
-18 ≤ 3x
-6 ≤ x
x ≥ -6
91 ! just use a calculator or do it by hand
Alright, this one is a little interesting... Let's perform some tests to figure out what is happening:
f(-10) = -(1/(-10)^3) = -(1/-1000) = 1/1000 (positive)
f(-5) = -(1/(-5)^3) = -(1/-125) = 1/125 (positive, bigger than the last one)
f(-1) = -(1/(-1)^3) = -(1/-1) = 1 (positive, bigger than the last one)
f(-0.1) = -(1/(-0.1)^3) = -(1/-0.001) = 1/0.001 = 1000 (positive, bigger than the last one)
f(0) = -(1/0^3) = undefined!
f(0.1) = -(1/(0.1)^3) = -(1/0.001) = -1/0.001 = -1000 (negative)
f(1) = -(1/1^3) = -(1/1) = -1 (negative, but bigger than last one)
It's a little confusing with the undefined part at x = 0. What I can say is this, it is increasing from -10 up to 0, something weird happens at 0 and it resets, and starts increasing from 0 up to 0.1.
I guess A would be the best answer?
J=john
m=mary
j is 2 times as old as mary
j=2 times m
sum is 21
m+j=21
find mary
subsitute
j=2m therefor subsitute 2m for j
m+2m=21
add like terms
3m=21
divide by 3
m=7
mary=7
*HOPE I HELPED!*
and 
