x2 - 8x - 8y + 16 + y2 এর সঙ্গে কত যোগ করলে যোগফল একটি পূর্ণ বর্গ হবে?
A
4xy
B
2xy
C
6xy
D
8xy
উত্তরের বিবরণ
প্রশ্ন: x2 - 8x - 8y + 16 + y2 এর সঙ্গে কত যোগ করলে যোগফল একটি পূর্ণ বর্গ হবে?
সমাধান:
x2- 8x - 8y + 16 + y2
=x2 + y2 + 16 - 8x - 8y
=(x)2 + (y)2 + (- 4)2 + 2.x.y + 2.y.(- 4) + 2.(- 4).x - 2xy
=(x + y - 4)2 - 2xy
সুতরাং রাশিটির সাথে 2xy যোগ করলে রাশিটি পূর্ণবর্গ হবে।
0
Updated: 2 months ago
In what ratio should a mixture of 20% alcohol strength be mixed with a mixture of 60% alcohol strength to get a mixture of 50% alcohol strength?
Created: 1 month ago
A
1 : 2
B
3 : 2
C
1 : 3
D
2 : 3
Question: In what ratio should a mixture of 20% alcohol strength be mixed with a mixture of 60% alcohol strength to get a mixture of 50% alcohol strength?
Solution:
Let the ratio be 1 : x
Then according to the question
⇒ 20 × 1 + 60x = (1 + x) 50
⇒ 20 + 60x = 50 + 50x
⇒ 60x - 50x = 50 - 20
⇒ 10x = 30
⇒ x = 3
∴ the ratio is 1 : 3
0
Updated: 1 month ago
If x + 1/x = 2 then, find the value of x8 - 1/x8
Created: 1 month ago
A
0
B
8
C
64
D
32
Question: If x + 1/x = 2 then, find the value of x8 - 1/x8
Solution:
Given,
x + 1/x = 2
⇒ x2 + 1 = 2x
⇒ x2 - 2x + 1 = 0
⇒ x2 - 2 . x . 1 + 12 = 0
⇒ (x - 1)2 = 0
⇒ x - 1 = 0
∴ x = 1
∴ x8 - 1/x8 = 18 - 1/18
= 1 - 1
= 0
0
Updated: 1 month ago
a + b = 8 এবং a - b = 4 হলে ab = কত?
Created: 2 days ago
A
4
B
8
C
10
D
12
সমাধান:
দেওয়া আছে,
a + b = 8 এবং a - b = 4
প্রদত্ত রাশি,
ab = {(a + b)/2}2 - {(a - b)/2}2
= (8/2)2 - (4/2)2
= 42 - 22
= 16 - 4
= 12
0
Updated: 2 days ago
