Question

Urgent va rog ex. 5 si 6

Answer 1

ex 5.
a)
√20=2√5          3×2√5-3×3√5+4√5=6√5-9√5+4√5=√5
√45=3√5

b) (2-√3)²=2²-2×2√3+(√3)²=4-4√3+3=7-4√3

c) (√5-2)(√5+2)=√5×√5-2×√5+2×√5-2×2=5-4=1

d) (6-√2)²-(5+√2)²=38-12√2-27+10√2=11-2√2