Question

Find the value of polynomial 5x-4x^2+3 at x=1,x=-2 and x=-3​

Answer 1

Answer:

The value of a polynomial obtained on putting a particular value of the variable is called the value of the polynomial.

(i) p(x) = 5x – 4x² + 3

On putting x = 0 ,

p(0) = 5(0) – 4(0)² + 3

= 0 – 0 + 3

=3

p(0) = 3

(ii) p(x) = 5x – 4x² + 3

On putting x= -1,

p(-1) = 5(-1) – 4(-1)²+ 3

= -5 – 4(1) + 3

= -5 – 4 + 3

= -9 + 3

= -6

p(-1) = -6

(iii) p(x) = 5x – 4x² + 3

On putting x = 2

p(2) = 5(2) – 4(2)² + 3

= 10 – 16 + 3

= -6 + 3

p(2) = -3

Answer 2

☞ EQUATION → $\fbox{5x - {4x}^{2} + 3}$

(i) x = 1

Putting x = 1,

$→5(1) - 4{(1)}^{2} + 3$

$→5 - 4 + 3$

$→4$

❍ p(1) = 4

(ii) x = -2

Putting x = -2,

$→5(2) - 4{(2)}^{2} + 3$

$→10 - 16 + 3$

$→ - 3$

❍ p(-2) = -3

(iii) x = -3

Putting x = -3,

$→5(3) - 4{(3)}^{2} + 3$

$→15 - 36 + 3$

$→ - 18$

❍ p(-3) = -18