Question

Which of the identity is not correct?

Select one:
(a-b)^2 = a^2 - 2ab - b^2
(a+b)(a-b) = a^2 - b^2
(a-b)^2 = a^2 - 2ab + b^2
(a+b)^2 = a^2 + 2ab + b^2​

Answer 1

Step-by-step explanation:

The Theorem of Pythagoras

(a + b)2 = a2 + 2ab + b2 (recall that 2ab means 2 times a times b). For example 152 = (10 + 5)2 ...

(a - b) 2 = a2 - 2ab + b2 For example: 52 = (10 - 5)2 = 102 - (2)(10)(5) + 52 ...

(a + b) 2 = (4)(1/2)(a)(b) + c2 ...

a2 + 2ab + b2 = 2ab + c2 ...

a2 + b2 = c2

Answer 2

Step-by-step explanation:

hey mate here is your answer:

1)

given,

(a-b)^2 =a^2-2ab-b^2

.: it is wrong because (a-b)^2= a^2-2ab+b^2

2)

given,

(a+b)(a-b)= a^2-b^2

.: it is correct because by multiplying (a-b) (a+b)

we will get a^2-b^2.

3)

given,

(a-b)^2 = a^2 - 2ab + b^2

.:it is correct.

4)

given,

(a+b)^2 = a^2 + 2ab + b^2

.: it is also correct.

.: by checking all options we can conclude that "(a-b)^2 = a^2 - 2ab - b^2" is not correct