One of the zeroes of the polynomial 2 x2-7 x-4 isa 2b 12c -2d -12

(b) nbsp;12 Let: px=2x2+7x 4 px=0 #8658;2x2+7x 4=0 nbsp; nbsp; nbsp; nbsp; nbsp; #8658;2x2+8x x 4=0 #8658;2xx+4 1x+4=0 #8658;x+42x 1=0 ...

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Standard IX

Mathematics

Zeroes of a Polynomial

One of the ze...

Question

One of the zeroes of the polynomial 2x² + 7x − 4 is

(a) 2
(b) $\frac{1}{2}$
(c) −2
(d) $\frac{- 1}{2}$

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Solution

(b) $\frac{1}{2}$

Let:
$p (x) = 2 x^{2} + 7 x - 4$
$p (x) = 0 \Rightarrow 2 x^{2} + 7 x - 4 = 0$
$\Rightarrow 2 x^{2} + 8 x - x - 4 = 0 \Rightarrow 2 x (x + 4) - 1 (x + 4) = 0 \Rightarrow (x + 4) (2 x - 1) = 0 \Rightarrow x + 4 = 0 or 2 x - 1 = 0 \Rightarrow x = - 4 or x = \frac{1}{2}$
Hence, one of the zeroes of the given polynomial is $\frac{1}{2}$ .

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Similar questions

Q. On of the zeros of the polynomial f(x) = 2x² + 7x – 4 is
(a) 2
(b)

\frac{1}{2}

(c)

- \frac{1}{2}

(d) –2

Q. Question 10
One of the zeroes of the polynomial is

2 x^{2} + 7 x - 4

A) $2$
B) $\frac{1}{2}$
C) $- \frac{1}{2}$
D) $- 2$

Q. Question 10
One of the zeroes of the polynomial is

2 x^{2} + 7 x - 4

A) $2$
B) $\frac{1}{2}$
C) $- \frac{1}{2}$
D) $- 2$

The zeros of the polynomial $p (x) = 2 x^{2} + 7 x - 4$ are
(a) $4, \frac{- 1}{2}$
(b) $4, \frac{1}{2}$
(c) $- 4, \frac{1}{2}$
(d) $- 4, \frac{- 1}{2}$

Q. Question 2
A quadratic polynomial, who zeroes are -3 and 4, is
(a)

x^{2} - x + 12

(b)

x^{2} + x + 12

(c)

\frac{x^{2}}{2} - \frac{x}{2} - 6

(d)

2 x^{2} + 2 x - 24

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One of the zeroes of the polynomial 2x2 + 7x − 4 is (a) 2 (b) 12 (c) −2 (d) -12

(b) 12 Let: px=2x2+7x-4 px=0⇒2x2+7x-4=0 ⇒2x2+8x-x-4=0⇒2xx+4-1x+4=0⇒x+42x-1=0⇒x+4=0 or 2x-1=0⇒x=-4 or x=12 Hence, one of the zeroes of the given polynomial is 12.

One of the zeroes of the polynomial 2x² + 7x − 4 is

(a) 2
(b) $\frac{1}{2}$
(c) −2
(d) $\frac{- 1}{2}$