Question

Help Please need help

Answer 1

Table:

x      y

-3    0.5

-2    1

-1     2.5

0      5

1      8.5

Now, y = ax^2 + bx + c

Start replacing x = 0 and y = 5

5 = a(0) + b(0) + c => c = 5.

Now, replace any other two pair of data:

(-2, 1) => -1 = a(-2)^2 + b(-2)

-1 = 4a - 2b

(1, 8.5) => 8.5 = a(1)^2 + b(1)

8.5 = a + b

Solve the system

4a - 2b = - 1
a + b = 8.5

=>

4a - 2b = - 1
2a + 2b = 17
-------------------------

6a = 16

=> a = 16 / 6 = 8/3

b = 8.5 - a = 17/2 - 8/3 = 35/6

=> y = (8/3)x^2 + (35/6)x + 5 <--------- answer