(2 thousands 7 tens) times 10
1 answer:
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Answer: or
Step-by-step explanation:
We can convert from mixed numbers to decimal numbers:
Since they cleaned up 8.2 kilograms of trash in one neighborhood and 11.5 kilograms in another neighborhood, the total trash they cleaned up was:
We know that they sent 1.25 kilograms to be recycled. Then, in order to calculate how many kilograms of trash they threw away, we must subtract the total kilograms of trash they cleaned up and the kilograms they sent to be recycled.
Then:
or
9514 1404 393
Answer:
y = -2x^2 +7x +4
Step-by-step explanation:
A graphing calculator or spreadsheet can tell you the quadratic regression formula that will fit these points:
y = -2x^2 +7x +4
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If you'd like to do this "by hand", you can substitute the given points into the equation y = ax^2 +bx +c to get three linear equations in a, b, c.
4 = 0 +0 +c
10 = a(2^2) +b(2) +c
0 = a(4^2) +b(4) +c
Using the value of c from the first equation, these reduce to ...
6 = 4a +2b
-4 = 16a +4b
Dividing the second of these equations by 2, and subtracting the first, we have ...
(16a +4b)/2 -(4a +2b) = (-4)/2 -(6)
4a = -8
a = -2
From the first of the reduced equations, we find ...
b = (6 -4a)/2 = 3 -2a = 3 -2(-2) = 7
So, a=-2, b=7, c=4, and the equation is ...
y = -2x^2 +7x +4
