Practicing Success
If $x + y + z = 10, xy + yz + zx =25$ and $xyz = 100$, then what is the value of $(x^3 + y^3 + z^3)?$ |
540 450 550 570 |
550 |
Given , x + y + z = 10 xy + yz + zx = 25 xyz = 100 We know, x3 + y3 + z3 – 3xyz = (x + y + z) [(x + y + z)2 – 3 (xy + yz + zx)] x3 + y3 + z3 – 3 × 100 = 10 [102 – 3 × 25] x3 + y3 + z3 – 300 = 10 (100 – 75) = 10 × 25 = 250 x3 + y3 + z3 = 250 + 300 = 550 |