Q4 of 90 Page 33

Expanding the following using suitable identities.

(3a – 7b – c)2

Using identity:

(x + y + z)2 = x2 + y2 + z2 + 2xy + 2yz + 2zx


(3a + (– 7b) + (– c))2 = (3a)2 + (– 7b)2 + (– c)2 + 2(3a)(– 7b) + 2(– 7b)(– c) + 2(– c)(3a)


= 9a2 + 49b2 + c2 – 42ab + 14bc – 6ac


More from this chapter

All 90 →
4

Expanding the following using suitable identities.

(a + 2b + 4c)2

 4

Expanding the following using suitable identities.

(m + 2n – 5p)2

 4

Expanding the following using suitable identities.

 5

Factorize :

9x2 + 4y2 + 16z2 – 12 xy – 16yz + 24 xz