Answer:
a = 2, b = -9, c = 3
Step-by-step explanation:
Replacing x, y values of the points in the equation y = a*x^2 + b*x +c give the following:
(-1,14)
14 = a*(-1)^2 + b*(-1) + c
(2,-7)
-7 = a*2^2 + b*2 + c
(5, 8)
8 = a*5^2 + b*5 + c
Rearranging:
a - b + c = 14
4*a + 2*b + c = -7
25*a + 5*b + c = 8
This is a linear system of equations with 3 equations and 3 unknows. In matrix notation the system is A*x = b whith:
A =
1 -1 1
4 2 1
25 5 1
x =
a
b
c
b =
14
-7
8
Solving A*x = b gives x = Inv(A)*b, where Inv(A) is the inverse matrix of A. From calculation software (I used Excel) you get:
inv(A) =
0.055555556 -0.111111111 0.055555556
-0.388888889 0.444444444 -0.055555556
0.555555556 0.555555556 -0.111111111
inv(A)*b
2
-9
3
So, a = 2, b = -9, c = 3
Answer:
The sum of two numbers is 84:
u + y = 84
The difference of the two numbers is 32:
u - y = 32
11
subtract 9 to both sides
Answer:
Given no. of persons owned laptop = 76
Total of no. of students owned + Total of no. of students dont have owned laptop given = 155
No. of students dont have laptops = 155 - 76 = 79
So then the total no. of no laptops = 79 + 17 = 96(ans)
Answer:
$1000.
Step-by-step explanation:
Let x represent number of years.
We have been given that Tommy purchased a riding lawnmower with an original value of $2,500. The value of the riding lawnmower decreases by $300 per year. We are asked to find the value of lawnmower after 5 years.
Since the value of the riding lawnmower decreases by $300 per year, so value of lawnmower decrease in 5 years would be 5 times $300.
The final value of lawnmower would be initial value minus value decreased in 5 years.
Therefore, the value of lawnmower after years would be $1000.
