2.
a)[tex] \sqrt{(2 \sqrt{10} +6)(2 \sqrt{10}-6) } = \sqrt{40-36} = \sqrt{4} =2[/tex]
b)√288=√(2·12²)=12√2
√98=√(2·7²)=7√2
12√2-7√2=5√2
5√2=√(2·5²)=√50 =>n=50
c)7=√49 ; 5√2=√50 =>5√2>7
3.
a)x(3x²-4):(-x)+3x=
-(3x²-4)+3x=
4-3x²+3x
Personal, cred ca exercitiul este gresit tiparit. Acolo, in loc de x³ e doar x² si atunci exercitiul arata asa :
x(3x-4):(-x)+3x=
-3x+4+3x=
4
b)(x+2)(x+2-2)=
x(x+2)
