Question

slove the problem 6.19*6.19*6.19-4.69*4.69*4.69-4.5*6.19*4.69

Answer 1

6.19*6.19*6.19-4.69*4.69*4.69-4.5*6.19*4.69

4.5 = 3 ×1.5 = 3 × (6.19 - 4.69)

=6.19*6.19*6.19-4.69*4.69*4.69-3×(6.19 -4.69)6.19*4.69

using (a +b)^3 or ( a -b)^3 identity

a = 6.19

b = -4.68

(a +b)^3 = a^3 + b^3 + 3ab(a+b)

= 6.19^3 + (-4.69)^3 + 3*6.19 *(-4.69)(6.19 - 4.69)

=6.19*6.19*6.19-4.69*4.69*4.69-3×(6.19 -4.69)6.19*4.69

= (6.19 - 4.69)^3

= 1.5^3

= 15^3/10^3

= 3375/1000

= 3.375