Question

if a + b = 15 and ab = 36 find the value of A^3+b^3​

Answer 1

Answer:

9+6= 15 and a*b=36 is 9*4 = 36

Answer 2

Answer:

a^3+b^3 = 1755

Step-by-step explanation:

a + b = 15 -----eq(1)

ab = 36 -------eq(2)

a=36/b -------eq(3)

Put eq(3) in eq(1)

36/b + b = 15

36 + b^2 = 15b

b^2 - 15b + 36 = 0

(b^2 - 3b) - (12b - 36) = 0

b(b-3) -12(b-3) = 0

(b-3)(b-12) = 0

b-3 = 0 or b-12 = 0

b = 3 b = 12

Case 1 :

If b=3

a=36/3

a=12

a^3 + b^3 = 12^3 + 3^3 = 1728 + 27 = 1755

Case 2 :

If b=12

a=36/12

a=3

a^3+b^3 = 3^3 + 12^3 = 27 + 1728 = 1755

a^3+b^3 = 1755