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xxemoxx:
I have a question
Show that the curves y=2x^2 + 5x , y= x^2 + 4x + 12, y=3x^2 + 4x - 6 have one point in common and find its coordinate   its from the book P1 Mathematics ( AS LEVEL CAMBRIDGE)
 thanks
i need an urgent solution pleasee..
cheers:D

astarmathsandphysics:
1)y=2x^2 + 5x
2)7=x^2 + 4x + 12
3)y=3x^2 + 4x - 6
1)=2) 2x^2 + 5x =x^2 + 4x - 12
x^2+x-12=0=(x+4)(x-3) so x=-4,3
1)=3)2x^2 + 5x =3x^2 + 4x - 6
so x^2-x-6= 0 so (x+2)(x-3)=0 so x=-2,3
2)=3)x^2 + 4x +12=3x^2+4x-6 so2x^2-18=0 so x^2=9 so x=3, -3
ans is x=3
y=x^2+4x+12=9+12+12=33

xxemoxx:
hey, thanks alot it really helped.

xxemoxx:
I have another question
The line y = 6x + 1 meets the curve y=x^2 + 2x + 3 at two points. Answers are in surds..
source: Q22 P1 AS LEVEL maths cie

astarmathsandphysics:
6x + 1=x^2 + 2x + 3
x^2-4x+2=0
x=(-b+_sqrt(b^2-4ac))/2a=(4+-sqrt(16-8))/2=2+-sqrt(2)

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