Advertisements
Advertisements
Question
Evaluate, using (a + b)(a - b)= a2 - b2.
399 x 401
Sum
Advertisements
Solution
399 x 401
= (400 - 1) x (400 + 1)
= (400)2 - (1)2
= 160000 - 1
= 159999.
shaalaa.com
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
Expand the following, using suitable identity:
(–2x + 5y – 3z)2
If 9x2 + 25y2 = 181 and xy = −6, find the value of 3x + 5y
Simplify `(x^2 + y^2 - z)^2 - (x^2 - y^2 + z^2)^2`
If x = 3 and y = − 1, find the values of the following using in identify:
(9y2 − 4x2) (81y4 +36x2y2 + 16x4)
Evalute : `( 7/8x + 4/5y)^2`
If a - b = 4 and a + b = 6; find
(i) a2 + b2
(ii) ab
Simplify by using formula :
(5x - 9) (5x + 9)
Simplify by using formula :
(2x + 3y) (2x - 3y)
Evaluate the following :
1.81 x 1.81 - 1.81 x 2.19 + 2.19 x 2.19
Simplify (2x – 5y)3 – (2x + 5y)3.
