Question : If $4x^2+y^2 = 40$ and $xy=6$, then the value of $2x-y$ is:
Option 1: 1
Option 2: 3
Option 3: 4
Option 4: 2
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Correct Answer: 4
Solution : Consider, $2x-y$ Squaring this equation, we get, $(2x-y)^2=4x^2+y^2-4xy$ Given, $4x^2+y^2 = 40$ and $xy=6$ ⇒ $(2x-y)^2=40-4\times 6$ ⇒ $(2x-y)^2=40-24=16$ ⇒ $2x-y=\sqrt{16}$ ⇒ $2x-y=4$ Hence, the correct answer is 4.
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Question : The algebraic expression $4x^2-y^2+6y-9$ is equal to______.
Option 1: $(2x + y - 3)(2x - y + 3)$
Option 2: $(2x - y - 3)(2x - y + 3)$
Option 3: $(2x + y - 3)^2$
Option 4: $(2x + y + 3)^2$
Question : If $\small x+y+z=6$ and $xy+yz+zx=10$, then the value of $x^{3}+y^{3}+z^{3}-3xyz$ is:
Option 1: 36
Option 2: 48
Option 3: 42
Option 4: 40
Question : Simplify the expression: $(2x+13-y)(2x-13-y)$
Option 1: $4x^2-y^2-4xy-169$
Option 2: $4x^2+y^2+4xy-169$
Option 3: $4x^2+y^2-4xy-169$
Option 4: $4x^2+y^2-4xy+169$
Question : If $\sin^4x + \sin^2x = 1$, then what is the value of $\cot^4x+ \cot^2x$?
Option 1: –2
Option 2: 2
Option 3: –1
Option 4: 1
Question : If $2x-3(4-2x)<4x-5<4x+\frac{2x}{3}$, then $x$ can take which of the following values?
Option 1: 2
Option 2: 8
Option 3: 0
Option 4: –8
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