Question

Find the value 407 × 405 by suitable identify

Answer 1

Answer:

164835

Step-by-step explanation:

we can treat 400 as x, then it can be written as:-

(x+7)*(x+5)

we will use the theoram 4 of class 9th polynomials:-

x^2 +(7+5)(x) + (7)*(5)

x^2 +12x + 35

(now putting x as 400)

(400)^2 +12(400) + 35

160000+4800+35

164835

Answer 2

• We have to evaluate the above expression by using the given data.

        Given data:- $407\times405.$

        To find:- Value of given expression=?

        Solution:-

• Multiplication is denoted by the symbol(x).

• Multiplication is a method to get the product by multiplying two or more values.

• Using identity,

      $(x+a)(x+b)=x^{2}+(a+b) x+a b \text$

         we get,

       $407\times405\\=>(400+7)(400+5)\\=>400^{2} +(7+5)400+7\times5\\=>160000+(12)400+35\\=>160000+4800+35\\=>164835.$

      Hence we will get the value is $407\times405=164835.$