Advertisements
Advertisements
प्रश्न
If p + q = 8 and p - q = 4, find:
pq
Advertisements
उत्तर
(p + q)2 = (8)2
p2 + q2 + 2pq = 64 ...(i)
(p - q)2 = (4)2
p2 + q2 - 2pq = 16
p2 + q2 = 16 + 2pq ...(ii)
Using (ii) in (i), we get :
16 + 2pq + 2pq = 64
⇒ 4pq
= 64 - 16
= 48
⇒ pq = 12.
APPEARS IN
संबंधित प्रश्न
Without actually calculating the cubes, find the value of the following:
(28)3 + (–15)3 + (–13)3
Write in the expanded form:
`(a + 2b + c)^2`
Simplify of the following:
If \[x^4 + \frac{1}{x^4} = 119\] , find the value of \[x^3 - \frac{1}{x^3}\]
Find the following product:
\[\left( \frac{3}{x} - \frac{5}{y} \right) \left( \frac{9}{x^2} + \frac{25}{y^2} + \frac{15}{xy} \right)\]
If a + b = 8 and ab = 6, find the value of a3 + b3
If a - b = 0.9 and ab = 0.36; find:
(i) a + b
(ii) a2 - b2.
Use the direct method to evaluate :
(2a+3) (2a−3)
Expand the following:
(m + 8) (m - 7)
Find the value of x3 – 8y3 – 36xy – 216, when x = 2y + 6
