Thread: Can you... Prove that

Hello all, wondering if you could give me a hand,

Prove that the equation 4=x(2-x) has no real roots.

Thanks in advance,

Max

Expand, move everything to one side, so that you have a quadratic of the form .

Then check the discriminant. If the discriminant is negative, then there are not any real roots.

Thanks a lot, I get it now.

Max

Originally Posted by Max888

Hello all, wondering if you could give me a hand,

Prove that the equation 4=x(2-x) has no real roots.

Thanks in advance,

Max

Alternatively, here's how Fred Flinstone might have done it...









To get a we need a instead of 1

or a instead of

Apart from those, we need or

or

or etc, etc none of which can differ by 2

Much quicker to know the "abc" formula.

Right, thanks a lot!