Advertisements
Advertisements
Question
If a + b = 25 and a2 + b2 = 225, then find ab.
Advertisements
Solution
Given, a + b = 25 and a2 + b2 = 225
We know that,
(a + b)2 = a2 + b2 + 2ab ...[An algebraic identity]
⇒ (25)2 = 225 + 2ab
⇒ 2ab = (25)2 – 225
⇒ 2ab = 625 – 225
⇒ 2ab = 400
⇒ `ab = 400/2`
⇒ ab = 200
APPEARS IN
RELATED QUESTIONS
Use a suitable identity to get the following products.
(1.1m − 0.4) (1.1 m + 0.4)
Simplify (a2 − b2)2
Expand (ax + by)2
Use the formula to find the value.
502 × 498
Use the formula to find the value.
54 × 46
Use the formula to find the value.
98 × 102
Using identity, find the value of (100.1)2
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
4x4 + 12x3 + 9x2
Verify the following:
(7p – 13q)2 + 364pq = (7p + 13q)2
Find the length of the side of the given square if area of the square is 625 square units and then find the value of x.
