Advertisements
Advertisements
प्रश्न
If a – b = 3 and ab = 10, find : a3 – b3.
Advertisements
उत्तर
a − b = 3
⇒ (a − b)3 = (3)3
⇒ a3 − b3 − 3ab (a − b) = 27
⇒ a3 − b3 − 3×10 (3) = 27
⇒ a3 − b3 − 90 = 27
⇒ a3 − b3 = 27 + 90
⇒ a3 − b3 = 117
Alternative Method :
(a − b)3 = a3 − b3 − 3ab (a − b)
⇒ (3)3 = a3 − b3 − 3×10 (3)
⇒ 27 = a3 − b3 − 90
⇒ 27 + 90 = a3 − b3
⇒ 117 = a3 − b3
⇒ a3 − b3 = 117
APPEARS IN
संबंधित प्रश्न
If a+b=5 and ab = 6, find a2 + b2
If a2 + b2= 10 and ab = 3; find : a – b
If `"a" + 1/"a"=3`, find `"a"^2+1/"a"^2`
If a + b = 6 and ab = 8, find: a3 + b3.
If `3"x"+1/(3"x")=3`, find : `9"x"^2+1/(9"x"^2)`
The sum of the squares of two numbers is 13 and their product is 6. Find:
(i) the sum of the two numbers.
(ii) the difference between them.
If a2 + b2 = 41 and ab = 4, find : a – b
If 3x – 4y = 5 and xy = 3, find : 27x3 – 64y3.
If a + b = 8 and ab = 15, find a3 + b3.
The difference between the two numbers is 5 and their products are 14. Find the difference between their cubes.
