Advertisements
Advertisements
Question
If a + b = 5 and a2 + b2 = 13, then ab = ?
Options
12
6
5
13
MCQ
Advertisements
Solution
6
Explanation;
Hint: (a + b)2 = 25
13 + 2ab = 25
2ab = 12
ab = 6
shaalaa.com
Is there an error in this question or solution?
APPEARS IN
RELATED QUESTIONS
Use a suitable identity to get the following products.
(7a − 9b) (7a − 9b)
Find the following squares by suing the identities.
(2xy + 5y)2
Expand `("a"/2+"b"/3)^2`
Use the formula to multiply the following.
(a + 6) (a − 6)
Expand:
`("p"/3 + "q"/4)^2`
Simplify: (a + b)2 – 4ab
Factorise the following using suitable identity
y2 + 20y + 100
Factorise the following using suitable identity
36m2 + 60m + 25
Show that (x + 2y)2 – (x – 2y)2 = 8xy
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
x2 + 2x + 1
