If 9x² + y² = 37 and xy=2, x, y>0, then the value of (27x³ + y³) is:
27x3 + y3 = (3x + y) (9x2 + y2 – 3xy) = use (a + b)2 = a2 + b2 + 2ab = (3x + y)2 = ax2 + y2 + 6xy = (3x + y)2 = 37 + 6 × 2 = 49 = 3x + y = 7 = 27x3 + y3 = 7 × (37 – 3 × 2) = 27x3 + y3 = 7 × 31 = 217
366 276 196 126 66 ?
In each of the following questions, a number series is given. After the series a number is given followed by (a), (b), (c), (d) and (e). You have to com...
12 156 256 320 356 ?
...16 9 ? 13.25 22.625 36.3125
...3 4.5 6.75 10.125 15.1875 22.78125 ?
...542 541 532 507 458 ?
...18 19 28 53 102 ?
5, 11, 19, 29, 41, ?
60 61 126 387 ? 7845
5184, ?, 432, 144, 36, 12
