You can write two independent equations for x. Both must be satisfied for there to be a common solution. For example, from the first two of your equations:
2x^2 + 5x = x^2 + 4x +12
which can be rewritten
x^2 +x -12 = (x+4)(x-3) = 0
That has solutions of x=-4 and x=3.
You can also write:
x^2 + 4x + 12 = 3x^2 +4x -6
which is equivalent to
2x^2 = 18,
the solutions of which are
x = 3 or -3
Apparently there is a point at x = 3 that satisifies all of your equations. The y value at that point is 33. You can verify that with any of your first three equations.
So the answer is (3,33)
show that these curves
y=2x^2+5x
y=x^2+4x+12
y=3x^2+4x-6
have one point in common and find it coordinates??
is this done by simultaneous exuasion if so can you show me how because ive try and cant get it to work??
1 answer
1 answer