If 2a + 5b = 12 and ab = 3, find the value of $4a^2 + 25b^2$ ?

64 44 84 24

84

If 2a + 5b = 12 ab = 3, find the value of $4a^2 + 25b^2$ = ? we know that, If $K+l=n$ then, $K^2+l^2$ = n2 – 2 × k × l The value of $4a^2 + 25b^2$= 122 – 2 × 3 × 2 × 5 = 144 - 60 = 84