Answer:
Explanation:
Step 1: Quadratic equation is y = a
+ bx + c
Step 2: As you can see one of the points from graph is (0, -2). Now we can plug in x = 0 and y = -2 in the equation
-2 = a
+ b (0) + c
c = -2
One of the points given is (2, -6). Let’s plug in these values and make an equation. Call it equation A.
-6 = a
+ b(2) + c
-6 = 4a + 2b + c
Also, (5, 3) is another point given. Let’s plug in these values and make an equation. Call it equation B.
3 = a
+ b(5) + c
3 = 25a + 5b + c
Step 3: Substitute c = -2 in equation A and equation B
4a + 2b + c = -6
4a + 2b - 2 = -6
4a + 2b = -6 + 2
4a + 2b = -4
Divide both sides by 2
2a + b = -2
Now substitute c = -2 in equation B
25a + 5b + c = 3
25a + 5b - 2 = 3
25a + 5b = 5
Divide both sides by 5
5a + b = 1
Step 4: Solve the two equations from step 3 by subtracting
2a + b -5a - b = -2 - 1
-3a = -3
a = 1
Now plug in a=1 in any of the two equations to find b.
2(1) + b = -2
2 + b = -2
b = -4
Step 5: Replace a, b and c with their values in the quadratic equation
y = 1.
- 4x - 2
y =
- 4x -2
Answer: y =
- 4x - 2