AI generatedAlgebraKS3 / GCSE

Sketching a quadratic from its factors

Sketching a quadratic from its factors.

  • Roots are where . The turning point is the minimum or maximum.
  • The axis of symmetry is the vertical line through the turning point.
  • A positive coefficient opens upwards; a negative coefficient opens downwards.

Example 1

Sketch the quadratic, marking its roots and turning point.

Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−8−6−4−22−22468100

Example 2

Sketch the quadratic, marking its roots and turning point.

Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−8−6−4−22−10−8−6−4−220

Your turn

Question 1

Sketch the quadratic, marking its roots and turning point.

Check answer
Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−6−4−22−22468100
Question 2

Sketch the quadratic, marking its roots and turning point.

Check answer
Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−6−4−224−10−8−6−4−220
Question 3

Sketch the quadratic, marking its roots and turning point.

Check answer
Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−4−224−22468100
Question 4

Sketch the quadratic, marking its roots and turning point.

Check answer
Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−4−2246−10−8−6−4−220
Question 5

Sketch the quadratic, marking its roots and turning point.

Check answer
Set each factor equal to zero to find the roots.The axis lies halfway between the roots.Substitute this -value to find the turning point.The coefficient of decides whether the parabola opens upwards or downwards.
Roots , ; turning point .
Coordinate graph−2246−22468100