Question

Calculati: a) (a+2)(a-2); b) (x+1)(x-1) ; c) (7-y)(7+y); d) (x+3)(x-3); m (radical din 3 plus 1 supra radical din 3 )(radical din 3 minus 1 supra radical din 3 )​

Answer 1

a)

${a}^{2} - {2}^{2} = {a}^{2} - 4$

b)

${x}^{2} - {1}^{2} = {x}^{2} - 1$

c)

${7}^{2} - {y}^{2} = 49 - {y}^{2}$

d)

${x }^{2} - {3}^{2} = {x}^{2} - 9$

e)

${ \sqrt{3} }^{2} - { \frac{1}{ \sqrt{3} } }^{2} = 3 - \frac{1}{3} = \frac{2}{3}$