Factories:
100 – (x – 5)2
Given,
By using the formula a2 – b2 = (a + b)(a – b)
We get,
100 – (x – 5)2 = (10)2 – (x – 5)2
= {10 + (x – 5)}{10 – (x – 5)}
= (10 + x - 5)(10 – x + 5)
= (5 + x)(15 – x)