Question
If a3 = 117 + b3 and a = 3 + b,
then the value of a + b is:Solution
a3 – b3 = 117 and a – b = 3 ⇒ a3 – b3 = (a – b) (a2 + b2 +ab) ⇒ 117 = 3 (a2 + b2 +ab) ⇒ 39 = a2 + b2 +ab ⇒ a2 + b2 = 39 – ab we Know that (a-b)² = a2 +b² - 2ab = (a-b)² = 39 – ab – 2ab = (a-b)² = 39 – 3ab 9 = 39 – 3ab = ab = 10 Now use (a+b)² = a2 + b2 + 2ab (a+b)² = 39 – ab + 2ab (a+b)² = 39 + ab = 39 + 10 (a+b)² = 49 = a + b = ±7
(78.03 + 116.98) ÷ 13.211 = 89.9 – 25.23% of ?
- What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)
? = 49.83% of 39.72% of (45.011.99 – 4.98 2.04)
(8000)1/3 × 10.11 × 8.97 ÷ 18.32 = ? + 25.022
What approximate value will come in place of the question mark (?) in the following question? (Note: You are not expected to calculate the exact value.)...
(17.17 × 21.98) + 34.15% of 649.99 = ? + 125.34
Which of the following options is the closest approximate value which will come in place of question mark (?) in the following equation?
26.52 ×...
7952.64 - 5236.19 + 6892.57 + ? = 16100.84
(12.13) 2 - 19.93 + 39.78 - 42.93 = ?
45.45 × 11.67 + 14399.88 ÷ 8.01 + 124.79 = ?