The point (-1, 3) is the turning point of the graph with equation y = x2 + ax + b,
where a and b are integers.
Find the values of a and b.


Sagot :

Answer:

a = 2

b = 4

Step-by-step explanation:

Δy   = 2x + a.................for turning point, Δy/Δx = 0.

Δx

0 = 2x + a

x = -a/2.........from ( -1, 3), x = -1...............so,

-1 = -a/2.................a = 2.

y = x^2 + ax + b.

y = 3  ,    a = 2.................substitute.

3 = (-1)^2 + 2(-1) + b

3 = 1 -2 + b

b = 4

Answer:

The turning point of a parabola is the vertex

Vertex form of a quadratic equation: [tex]\sf y=a(x-h)^2+k[/tex]

(where (h, k) is the vertex and a is the coefficient of the variable x²)

Given:

  • [tex]\sf y=x^2+ax+b[/tex]
  • vertex = (-1, 3)

Therefore, a = 1

Substituting a = 1 and the given vertex into the equation:

[tex]\sf \implies y=1(x-(-1))^2+3[/tex]

[tex]\sf \implies y=(x+1)^2+3[/tex]

[tex]\sf \implies y=x^2+2x+1+3[/tex]

[tex]\sf \implies y=x^2+2x+4[/tex]

Therefore, a = 2 and b = 4