Question

The expression 9x² - 289y² can't be factorised using the identity a²-b² = (a-b) (a+b) *​

Answer 1

Answer:

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