If 2x + y = 15 and xy = 18, then the value of (4x² - y²)
ATQ, We know that, (a- b)2 = (a + b2 - 4ab So, (2x - y)2 = (2x + y)2 - 4 × 2xy = 152 - 8 × 18 = 225 - 144 = 81 So, we can say that, (2x - y) = - 9, or, 9. Since, all the given options are positive, so we will consider the positive value of (2x - y) , as (2x + y) is given positive. We know that, a2 - b2 = (a + b) × (a - b) So, 4x² - y² = (2x)2 - y2 = (2x + y) × (2x - y) = 15 × 9 = 135 Alternate solution Through trial and error, we can observe that x = 6 and y = 3. So, required value = {4 × (6)2 - 32 } = (4 × 36) - 9 = 135
40% of (362 ÷ 0.05) = ?
2945 – 1508 + 3454 = ? + 2255
The sum of two numbers is 16 and their product is 63. The sum of their reciprocal is equal to:
√(?) ² = √7396 - √6889
108² + 99 X 98² =?
...√1444 + √729 – √2116 = ?
? (1/2) = 236 – 25 × 18/2 + 396 ÷ 22
226 x 15 - 11 x 99 + (41)2 = ?