using : (a^2-b^2) =(a+b)(a-b) find 153^2-147^2
Answers
Answer:
An identity is true only for certain values of its variables. An equation is not an identity.
The following are the identities
(a + b)² = a² + 2ab + b²
(a – b)² = a² – 2ab + b²
(a – b)(a + b) = a² – b²
Another useful identity is
(x + a) (x + b) = x² + (a + b) x + ab
If the given expression is the difference of two squares we use the formula
a² –b² = (a+b)(a-b)
• The above four identities are useful in carrying out squares and products of algebraic expressions. They also allow easy alternative methods to calculate products of numbers and so on.
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Solution:
Using a²– b²= (a + b) (a – b)
1) 51²– 49²
= (51 + 49)(51 - 49)
= 100 x 2
= 200
2) (1.02)²– (0.98)²
= (1.02 + 0.98)(1.02 - 0.98)
= 2 x 0.04
= 0.08
3) 153²– 147²
= (153 + 147)(153 - 147)
= 300 x 6
= 1800
4) 12.1²– 7.9²
= (12.1 + 7.9)(12.1 - 7.9)
= 20 x 4.2
= 84
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Hope this will help you.....
Step-by-step explanation:
Answer:
(153)^2-(147)^2=(153-147)
=300×6=1800