blueseas wrote:

mridulparashar1 wrote:

If ab > 0, does (a - 2)(b - 2) = 4 ?

(1) 2a + 2b = ab

(2) a = b

I don't agree with OA here. Experts can you please confirm whether the OA is correct.

Reasoning for 2nd statement will be appreciated

\(ab > 0\)

MEANS\(a,b\) have same signs and \(a,b\) is not equal to zero.

(1)\(2a + 2b = ab\)

\(2a+2b-ab=0\)

subtracting 4 from both sides

\(2a-ab-4+2b=-4\)

\(a(2-b)-2(2-b)=-4\)

\((a-2)(2-b)=-4\)

or

\((a-2)(b-2)=4\)

sufficient.(2) \(a = b\)

let say \(a=b=2\) then \((a-2)(b-2) = 0\).....

NOlet\(a=b=4\) then\((a-2)(b-2) = 4\).....

YESnot sufficienthence

AHi Blueseas and Bunuel,

Thanks for your response.

Actually for st 2, I just plugged in the given statement a=b

to the equation which is being tested and ended up with b^2-4b=0 ie b=4= a and answer to the equation is (a - 2)(b - 2) = 4 YES

since the given equation is itself (a - 2)(b - 2) = 4 then there should have been another way to plug in the same considering

(b-2)^2

~~=~~ 4 or b-2

~~=~~ 2 or b-2

~~=~~-2

Since we do not the values of a and b the ans should be A and not D as I thought

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