The domain for which functions $f(x) = 2

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Target Exam

CUET

Subject

Mathematics

Chapter

Relations and Functions

Question:

The domain for which functions $f(x) = 2x^2-1$ and $g(x)=1-3x$ are equal, is

Options:

{2, -1/2}

{-2, 1/2}

{1, 2}

{-2, -1/2}

Correct Answer:

{-2, 1/2}

Explanation:

The correct answer is Option (2) → $\{-2, 1/2\}$

We have,

$f(x) = g(x)$

$⇒ 2x^2-1=1-3x$

$⇒2x^2+3x-2=0⇒ (2x-1) (x+2)=0⇒ x=-2,1/2$

Hence, $f(x) = g(x)$ for all $x = \{-2, 1/2\}$