Practicing Success
If $x - y = 4 $ and $x^3 - y^3 = 316 $, then the value of $x^4 + y^4 $ is : |
2248 2482 2428 2284 |
2482 |
x - y = 4 x3 – y3 = 316 We know that, x3 – y3 = (x - y)[(x - y)2 + 3xy] = 316 = 4[(x - y)2 + 3xy] = 79 = [16 + 3xy] = 63 = 3xy = xy = 21 = x = 7 then, y = 3 x4 + y4 = 74 + 34 = 2482 |