Question

Desfaceti parantezele:
1. ($\sqrt{3}$ + 7)($\sqrt{3}$ - 7) =

2. ($\sqrt{12}$ - 5)(2$\sqrt{5}$+ 12) =

3. (2$\sqrt{2}$ + 1)(3$\sqrt{2}$ - 4) =

4. ( 5$\sqrt{7}$ - $\sqrt{13}$)($\sqrt{13}$ + 5$\sqrt{7}$) = 

Answer 1

1.   ( + 7)( - 7) = (√3) la patrat  - 7 la patrat = 3-49 = -46
2    ( - 5)(2+ 12) =(2√3-5)(2+ 12)=4√15+24√3-10√5-60
√12=2√3
3.    (2 + 1)(3 - 4) =12-8√2+3√2-4=8-5√2
4.    ( 5 - )( + 5) =175-13=162

Answer 2

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