Question

If (a+b)=4 and ab=3, find the value of a3+b3​

Answer 1

Answer:

ab=3

a=b/3

(a+b)=4

3/b+b=4

b=3 or b=1

a=3 or a=1

this a3+b3=12

Answer 2

It is given that,

$(a + b) = 4 \\ a \times b = 3$

We have to find the value of a³ + b³

Hence, we use the formula:-

${a}^{3} + {b}^{3} = {(a + b)}^{3} - 3 a b(a + b)$

Substituting the given values, we get:-

${a}^{3} + {b}^{3} = {(4)}^{3} - 3 \times (3) \times (4) \\ {a}^{3} + {b}^{3} = 64 - 9 \times 4 \\ {a}^{3} + {b}^{3} = 64 - 36 \\ {a}^{3} + {b}^{3} = 28$

Therefore, the value of a³+b³ is 28.

Hope it helps you.