Advertisements
Advertisements
Question
If x + y = 9, xy = 20
find: x2 - y2.
Sum
Advertisements
Solution
x + y = 9, xy = 20
We know (x - y) (x + y)
= x2 - y2
⇒ x2 - y2
= (±1) (9)
= ±9.
shaalaa.com
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
Write the following cube in expanded form:
`[3/2x+1]^3`
Evaluate the following using suitable identity:
(102)3
Evaluate of the following:
1043 + 963
Find the following product:
(x3 + 1) (x6 − x3 + 1)
75 × 75 + 2 × 75 × 25 + 25 × 25 is equal to
Use the direct method to evaluate :
(4+5x) (4−5x)
Evaluate the following without multiplying:
(103)2
Simplify:
(7a +5b)2 - (7a - 5b)2
Expand the following:
(3a – 5b – c)2
Expand the following:
`(1/x + y/3)^3`
