Answer:
315 hours
Step-by-step explanation:
Good luck
Answer:
- Dien - 15 seconds, Jane - 10 seconds
Step-by-step explanation:
<u>Together:</u>
- 2/3 of pizza ⇒ 4 seconds
- Full pizza ⇒ 4 ÷ 2/3 = 6 seconds
Dien needs x seconds to eat pizza
Jane needs x - 5 seconds to eat pizza
<u><em>In one second, Dien can eat 1/x, Jane can eat 1/(x - 5), together 1/6 of a pizza</em></u>
- 1/x + 1/(x - 5) = 1/6
- x(x - 5) = 6(x + x - 5)
- x² - 5x - 12x + 30 = 0
- x² - 17x + 30 = 0
- (x - 15)(x - 2) = 0
- x = 15 (x = 2 is discounted as not realistic)
Dien can eat a pizza in 15 seconds, Jane can eat a pizza in 10 seconds
The answer is 10
............
3 is the leading coefficient of the x term
They cancel out each other
Imagine if you were multiplying
-2 * -3
you would get 6
if you did
-2 * 3
you would get -6 because there isn't another - to cancel it out
I learned it that when you have a negative before a negative, put parenthesis around the second number with the negative, so it looks like this
-(-2)
if you look at the -(- it looks like a plus sign
that probably doesn't make much sense but we cancelling it out is just a rule, we don't really know why we do it