vaivish1723 wrote:

IF x(X-5)(X+2)=0 is x negative?

1.x sq.2-7x is not equal to 0

2. x2-2x-15 is not equal to O.

Please help. OA is [img]c[img]

Fact: \(x(x-5)(x+2)=0\)

Question:( x<0 )?

Interpret fact to get that x=0,5 or -2, in the first 2 cases we have NO, in the last one we have a YES.

So we need more data.

(1) \(x*sqrt(7x) != 0\) (correct me if I read this wrong)

This means that x != 0 & that sqrt(7x) != 0. I don't think this is an Official question (GRRRR) or a very

poorly formulate one, but we can't test x=-2 as the square root of a negative number is a complex number... So if we can use complex numbers, insufficient, and if we aren't allowed to take the square root of a negative number, sufficient, as X can only be 5. But I'm going to go with Insufficient.

(2) \(x^2 - 2x - 15 != 0\)

Factorize the quadratic,

\(x^2 - 5x + 3x - 15 != 0\)

\(x(x - 5) + 3(x - 5) != 0\)

\((x-5)(x+3) !=0\)

So X can't be 5 or -3, but it can still be 0 or -2. Insufficient.

(1&2)

From original equation: x=0,5,-2

1 eliminates 0

2 eliminates 5

Only x=-2 remains

Final Answer,

C.

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Hades