Question

Calculati folosind formula (a-b)(a+b)=a (la puterea a doua) - b ( tot la puterea a doua)
a) (3-√2)(3+√2) + (√7-1)(√7+1)
b) (2-√3)(2+√3) - (√5-1)(√5+1)
c) (2√5-1)(1+2√5)+(√13+7)(7-√13)
dau coroana. va rog dacă știți sa ma ajutati

Answer 1

a. (3-√2)(3+√2)+(√7-1)(√7+1)=
9-2+7-1=
9+7-2-1=16-2-1=14-1=13;
b. (2-√3)(2+√3)-(√5-1)(√5+1)=
4-3-5+1=
4+1-3-5=5-3-5=2-5=-3;
c. (2√5-1)(2√5+1)+(√13+7)(7-√13)=
20-1+49-13=
20+49-1-13=69-1-13=68-13=55;