Question

factorise 3 - 12 (a minus b) square​

Answer 1

Answer:

long process :

by using the formula,

(a-b)² = (a)²-2(a)(b)+(b)²

we get,

=>(3-12)² = (3)²-2(3)(12)+(12)²

=>(3-12)² = (9)-72+(144)

=>(3-12)²=81

shortcut :

(3-12)² = (-9)² = 81

Answer 2

Given expression is 3-12(a-b)²

It can be written as 3[1-4(a-b)²]

=>3[1²-2²(a-b)²]

=>3[1²-{2(a-b)}²]

(we know that a²-b²=(a+b)(a-b)

here, a=1 and b=2(a-b))

=>3[{1+2(a-b)}{1-2(a-b}]

=>3[(1+2a-2b)(1-2a+2b)]

=>3(1+2a-2b)(1-2a+2b)

3-12(a-b)²=3(1+2a-2b)(1-2a+2b)