Advertisements
Advertisements
प्रश्न
If a - b = 10 and ab = 11; find a + b.
Advertisements
उत्तर
a - b = 10, ab = 11
We know that :
(a - b)2 = a2 - 2ab + b2
⇒ (10)2 = a2 + b2 - 2 x 11
⇒ 100 = a2 + b2 - 22
⇒ a2 + b2
= 100 + 22
= 122
Using (a + b)2 = a2 + b2 + 2ab, we get
(a + b)2
= 122 +2(11)
= 122 + 22
= 144
⇒ (a + b)
= `sqrt(144)`
= ±12.
APPEARS IN
संबंधित प्रश्न
Expand the following, using suitable identity:
(2x – y + z)2
Write in the expanded form:
`(a + 2b + c)^2`
Write in the expanded form: `(x/y + y/z + z/x)^2`
If a + b = 6 and ab = 20, find the value of a3 − b3
If a + b + c = 9 and ab +bc + ca = 26, find the value of a3 + b3+ c3 − 3abc
Use identities to evaluate : (998)2
Use the direct method to evaluate :
`("a"/2-"b"/3)("a"/2+"b"/3)`
Evaluate: 20.8 × 19.2
Simplify:
(3a + 2b - c)(9a2 + 4b2 + c2 - 6ab + 2bc +3ca)
If a + b + c = 0, then a3 + b3 + c3 is equal to ______.
