Explanation

Given:

a + b = 4

ab = 3

The formula for a^3 + b^3 is:

a^3 + b^3 = (a + b)(a^2 - ab + b^2)

However, a simpler approach uses the identity:

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

Plugging in the values:

a^3 + b^3 = (4)^3 - 3(3)(4)

= 64 - 36

= 28