Question

Find the product:

• (x + 9) (x - 12)
• (2 + 3x) (2 - 3x)

Class 9th
Chapter 2: polynomials​

Answer 1

1....(x+12)(x+9)

x(x+9)+12(x+9)

x ^2+9x+12x+108

x ^2 +21x+108

2...using(a−b)(a+b)=a ^2−b ^2

For the above expression, keeping a=3x and b=2, we get

(3x+2)(3x−2)=(9x ^2 −4)

Answer 2

Answer:

Question:

Find the product of :-

• (x + 9) (x - 12)

• (2 + 3x) (2 - 3x)

Solution:

(x + 9) (x - 12)

➞ x² - 12x + 9x - 108

➞ x² - 3x - 108

━━━━━━━━━━━━━━━━

(2 + 3x) (2 - 3x)

By using Formula,

(a + b) (a - b) = a² - b²

➞ 2² - (3x)²

➞ 4 - 9x²

➞ -9x² + 4

Hope it's help you army ♡~