Evaluate :
(i) (6−xy)(6+xy)
(ii) (7x+23y)(7x−23y)
(iii) (a2b+2ba)(a2b−2ba)
(iv) (3x−12y)(3x+12y)
(v) (2a+3)(2a−3)(4a2+9)
(vi) (a+bc)(a−bc)(a2+b2c2)
(vii) (5x+8y)(3x+5y)
(viii) (7x+15y)(5x−4y)
(ix) (2a−3b)(3a+4b)
(x) (9a−7b)(3a−b)
Question 85 (xi)
Expand the following, using suitable identities.
(2a3+b3)(2a3−b3)
Use direct method to evaluate :
(i) (x + 1)(x - 1)
(ii) (2 + a)(2 - a)
(iii) (3b - 1)(3b + 1)
(iv) ( 4 + 5x)(4 - 5x)
(v) (2a + 3)(2a - 3)
(vi) (xy + 4)(xy - 4)
(vii) (ab + x^2)(ab - x^2)
(viii) (3x^2 + 5y^2)(3x^2 - 5y^2)
(ix) (z−23)(z+23)
(x) (35a+12)(35a−12)
(xi) (0.5 - 2a)(0.5 + 2a)
(xii) (a2−b2)(a2+b3)