Ok this inequality tells you the number of devices you can have before the new plan costs more than the old plan. The new plan expression is $4.50x + $94m = y ( total cost). The old plan is $175m = y (total cost). You can see m (number of months) in both equations, you don't need it this time since we're going to to compare both to one month. Since they're both equal to y you can make them equal to each other. $4.50x + $94 = $175. Now you want to figure when the new plan is less than the old plan you switch the equal sign for a less than sign. $4.50x + $94 < $175; this will help you find the inequality you want. From there just use algebraic steps to find that x has to less than 18 or
x < 18.
Answer:65
Step-by-step explanation:
This is known as Einstein's proof, not because he was the first to come up with it, but because he came up with it as a 15 year old boy.
Here the problem is justification step 2. The written equation
BC ÷ DC = BC ÷ AC
is incorrect, and wouldn't get us our statement 2, which is correct.
For similar triangles we have to carefully pair the corresponding parts to get our ratios right:
ABC ~ BDC means AB:BD = BC:DC = AC:BC so BC/DC=AC/BC.
Justification 2 has the final division upside down.
The formula can be written in the form ...
... T = (original temperature) + x·(change in temperature each minute)
The problem statement gives you the original temperature (21 °C) and tells you the temperature after 12 minutes. You have to use that information to figure out the change in temperature each minute.
The change in temperature in 12 minutes is (75 °C) - (21 °C) = 54 °C. That is the change in 12 minutes, so the change in 1 minute will be 1/12 of that:
... 54/12 = 4.5
Using this value in the equation for T, we have
... T = 21 + 4.5x
