**Practice Set 3.4 Polynomials Class 9th Mathematics Part I MHB Solution**

###### Practice Set 3.4

Question 1.

For x=0 find the value of the polynomial x2 – 5x + 5

Answer:

Put x = 0 throughout the polynomial

⇒ 02 – 5 × 0 + 5

x (0) = 5

Question 2.

If p(y) = y2 - 3√2 + 1 then find p(3√2)

Answer:

Put x = 3√2 throughout the polynomial

⇒ (3√2)2 – (3√2 × 3√2) + 1

⇒ (9 × 2) – (9 × 2) + 1

⇒ 18 – 18 + 1

p(3√2) = 1

Question 3.

If p(m) = m3 + 2m2 – m + 10 then p(a) + p(-a) =?

Answer:

Put x = a throughout the polynomial

(a)3 + 2 × (a)2 –a + 10

p (a) = a3 + 2a2 – a + 10

Put x = -a throughout the polynomial

(-a)3 + 2 × (-a)2 –(-a) + 10

p (-a) = -a3 + 2a2 + a + 10

p(a) + p(-a):

a3 + 2a2 – a + 10 + -a3 + 2a2 + a + 10

∴ p(a) + p(-a) = 4a2 + 20

Question 4.

If p(y) = 2y2 – 6y2 – 5y +7 then find p(2).

Answer:

Put x = 2 throughout the polynomial

= 2 × (2)2 – 6 × (2)2 – 5 × 2 + 7

= 8 – 24 – 10 + 7

= -19

∴ p(2) = -19