Question

The value of the polynomial
(1 Point)
5x - 4x2 + 3 when x = -1
-6
6
O 2
o – 2​

Answer 1

Here,

x = -1

Then,

$5x - 4x²+ 3 \\ = 5 \times ( 1- ) - 4 \times ( - 1)²+ 3 \\ = - 5 -4 + 3 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ = - 9 + 3 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\\ = -6 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

.°. 1st option (-6) is the correct option.

Answer 2

$\gray{\huge\sf Correct \: Question :-}$

The value of the polynomial

(1 point)

5x - 4x² + 3, when x = - 1

a) - 6

b) 6

c) 3

$\red{\huge\sf Correct \: Option :-}$

$\implies$Option a ( - 6)

$\blue{\huge\sf Given :-}$

$\to\sf 5x - 4x^{2} + 3, when \: x = - 1$

$\orange{\huge\sf To \: Find :-}$

$\to\sf Value \: of \: the \: polynomial$

$\green{\huge\sf Solution :-}$

We have,

• $\sf 5x - 4x^{2} + 3$

Substituting the given value of x we get,

$\sf= 5(- 1) - 4(-1)^{2} + 3$

$\sf= - 5 - 4 + 3$

$\sf= - 9 + 3$

$=\underline{\boxed{\blue{\sf- 6}}}$

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Additional Information :-

1) + × + = +

★ Example :-

• 5x × 3x = 15x²

2) + × - = -

★ Example :-

• 5x × ( - 3x) = - 15x²

3) - × - = +

★ Example :-

• ( - 5x) × ( - 3x) = 15x²

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