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
Using identities, evaluate 712
Using identities, evaluate (5.2)2
Using (x + a) (x + b) = x2 + (a + b) x + ab, find 103 × 98
Expand:
`("p"/3 + "q"/4)^2`
Use a formula to multiply of (x − 5)(x + 5).
Factorise the following using suitable identity
y2 + 20y + 100
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
4x2 + 12x + 9
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
9x2 + 24x + 16
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
9x2 + 30x + 25
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
`x^2/4 + 2x + 4`
