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
1) 6 - 5.55 = 0.45 feet (the difference between 6 and 5.55)
2) 0.45/6 * 100 = 7.5% (the percentage of error in Celina's measurement)
$88
Explanation:
Adults $12x5 = 60
Child $7x 4=28
60+28=88
0<x<1 and 0<y<1
x>0 so x is positive and y>0 so y is also positive.
When you multiply two positive numbers you always get a positive number, so the product of x and y must be positive, or greater than 0.
xy>0 - it must be true
xy<0 - it can't be true
Also when you divide a positive number by a positive number you always get a positive number, so the quotient of x and y must be positive.
x/y<0 - it can't be true
D and E can be true, but don't have to. It depends on the values of x and y. If x>y, then x-y>0 is true and x-y<0 isn't true; if x<y, then x-y>0 isn't true and x-y<0 is true.
Therefore, only A <u>must</u> be true.
The answer is 20, because it goes up every time.
