Mike4 wrote:mc2fool wrote:But I don't see how the above gets to supposed answer (2) ...
On further consideration I agree with you. It doesn't.
The question, clarified by the OP is 63x2 - 27x + 14x2 - 6x = ?
This strikes me as unsolvable without more info. Others have assumed 63x2 - 27x + 14x2 - 6x = 0 and have gone on to solve it as a quadratic but it isn't, as far as my plumbery maths goes. They are actually asking what 77x2 - 33x is equal to, so it is not safe to assume it is zero. So how would one go about solving it? I don't think it is possible without more info. Possibly this is why it is a multi-choice question, we can plug in each answer offered as a simultaneous equation and seef* it works.
Seef: verb, invented by my kids, a contraction of "see if".
The question isn't solve for x = 0 though is it?
The question is which of the mutliple choice answers a) to e) is equal to the expression on the left of the "="? It might be zero, or any other number (or equation).
If that is too obtuse imagine if the formula was 2+2 and your multiple choice answers were 3+1, 7-2, 4x2 etc. To prove it mathematically at no point are you needing to show that the answer "equals" 4. Just that 3+1 is "equal" to 2+2.