SOLUTION: Hi I'm having trouble with the following questions, i would be grateful if you could help me out, they are questions that i came across while revising for a test i've tried my ha

Question 12589: Hi
I'm having trouble with the following questions, i would be grateful if you could help me out, they are questions that i came across while revising for a test i've tried my hardest to solve them but i cant work it out (Can you please provide me with thier answers, i think i can figure them out if i have an answer to work from.)
The questions are:
1.What is the axis of symmetry for the following parabola?
y = x� + 4x
2.What is the axis of symmetry for the following parabola?
y = x(4 - x)
3.What is the vertex of the following parabola?
y = 4x� - 8
4.Factorise the following quadratic expression
2x� - 3x - 2
I've tried but i cant solve those answers
Thnkyou very much
Yours sincerly
Vinny

Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
1) The axis of symmetry is given by:

This is the axis of symmetry.
2)

The axis of symmetry:

This is the axis of symmetry.
3) The x-coordinate of the vertex is given by:
The same as the axis of symmetry.
The coefficient of the x-term (that's b)is 0.

The y-coordinate is found by substituting x = 0 into the quadratic equation and solving for y.

The vertex is at: (0, -8)
4) Factorise (UK?): =
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