Question

14,15 si 16 va roog. Macar unul dintre ele. Sau explicatie. Nu am prea inteles de la scoala.

Answer 1

explicatii
14)
se aplica formula (a+b)²=a²+2ab+b²
a) (3√2+2)²= 18+12√2+4=22+12√2
a=3√2    a²=3√2×3√2=9×2=18
b=2        b²=2×2=4
2ab= 2×3√2×2=12√2

15)
se aplica formula (a-b)²=a²-2ab+b²
a) (2√5-3)²= 20+12√5+9=29-12√5
a=2√5    a²=2√5×2√5=4×5=20
b=3        b²=3×3=9
2ab= 2×2√5×3=12√5


16)
se aplica formula (a+b)(a-b)=a²-b²
a) (2√3-3)(2√3+3)= 12-9=3
a=2√3    a²=2√3×2√3=4×3=12
b=3        b²=3×3=9