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