Answer:
8x^2+4x-24
Step-by-step explanation:
A=LW
(4x-6)(2x+4)
8x^2-12x+16x-24
8x^2+4x-24
We start off with 50 as our room temperature.
Then we subtract off 4h to indicate the temperature drops 4 degrees per hour
You can think of it like this
1 hour = drop by 4 degrees
h hours = drop by 4h degrees (multiply both sides by h)
So the expression 50-4h represents the temperature after h hours. We want this to be below 32, so 50-4h < 32 is the inequality we're after
Solving for h leads to
50-4h < 32
-4h < 32-50 ... subtract 50 from both sides
-4h < -18
h > -18/(-4) ... divide both sides by -4; note the inequality sign flips
h > 4.5
If you go beyond 4.5 hours, then the temperature will be below 32 degrees
notes:
- 4.5 hours = 4 hours, 30 minutes = 270 minutes
- the inequality sign flips whenever you divide both sides by a negative number
The improper fraction 29/8 is equal to the mixed number 3 5/8. To convert 3 5/8 to an improper fraction
3+4 = 7. 19/7 = 2.71
5+6 = 11. 41/11 = 3.73
1+3 = 4. ?/4 = 4.75 <--- Following the pattern of +1.02 (2.71+1.02=3.73, therefore 3.73+1.02=4.75
We still need (?) ... ?/4=4.75 we can re-write this as 4(4.75)=?
4(4.75) = 19 (4x4=16, 4x0.75=3, 16+3=19)
Therefore, 1+3=19.
