$$(1)\ \ (x^2+3)^2−11(x^2+3)+28=0.$$VJesus12 wrote:What is the value of x?
$$(1)\ \ (x^2+3)^2−11(x^2+3)+28=0.$$
$$(2)\ \ \ x^2+x−2=0.$$
The OA is E.
With statement two I can find the values of x. Why it is not sufficient?
Say y = (x^2 + 3), then
The equation look as y^2 -11y + 28 = 0
=> y^2 -7y - 4y + 28 = 0
=> y = 7 or 4
=> x^2 + 3 = 7 or x^2 + 3 = 4
From x^2 + 3 = 7, we get x = ±2 and from x^2 + 3 = 4, we get x = ±1. No unique value of x. Insufficient.
$$(2)\ \ \ x^2+x−2=0.$$
=> x^2 + 2x - x - 2 = 0
=> x = 1 or -2. No unique value of x. Insufficient.
(1) and (2) together:
Even from both the statements, we get that x is either -2 or 1. Insufficient.
The correct answer: E
Hope this helps!
-Jay
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