Using `a^2-b^2`=`(a+b)(a-b) 'find' `51^2-49^2`

Using a^2-b^2 = (a+b)(a-b) find 12.1^2-7.9^2

Using a^2-b^2 = (a+b)(a-b) find 153^2-147^2

Using a^2-b^2 = (a+b)(a-b) find (1.02)^2-(0.98)^2

Using (x+a)(x+b) = x^2+(a+b)x+ab find 5.1 xx 5.2

Using (x+a)(x+b) = x^2+(a+b)x+ab find 103 xx 98

Using (x+a)(x+b) = x^2+(a+b)x+ab find 103 xx104

Using (x+a)(x+b) = x^2+(a+b)x+ab find 9.7 xx9.8

If 2 (a^(2) + b^(2)) = (a + b)^(2) then :

a) Prove that int_(a)^(b)f(x)dx=int_(a)^(b)f(a+b-x)dx" and evaluate "int_(pi//6)^(pi//3)(dx)/(1+sqrt(tanx)) b) Prove that |{:(1+a^(2)-b^(2), 2ab, -2b), (2ab, 1-a^(2)+b^(2), 2a), (2, -2a, 1-a^(2)-b^(2)):}|=(1+a^(2)+b^(2))^(3)

Use the identity (x+a)(x+b) = x^2+(a+b)x +ab to find the following products (2a^2+9)(2a^2+5)