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
What will come in the place of question mark (?) in the given expression?
(√676 of √144 ÷ 13) of 2400% = ?
What value should come in the place of (?) in the following questions?
30% of 160 – 25% of 240 + 43 = ?
?= √(4 × ∛(16 × √(4 × ∛(16 ×…… ∝)) ) )
What will come in the place of question mark (?) in the given expression?
(24 2 – 16 2 ) + 75% of 40% of 480 = ?
(500 × 6 ÷ 10) - (√256 + 8) = ?
What value should come in the place of (?) in the following questions?
320 + 162 – 55% of 720 = 5 * ?2
What will come in the place of question mark (?) in the given expression?
If 840 ÷ 12 + 1025 ÷ 25 - n + 45 × 4 = 960 ÷ 16 × 132 ÷ 44, then the value of n is:
24 × ?2 – 11 × 4 = 1900
