Question

Va rog sa ma ajutati la exercitiile 2,3,4, va rog mult

Answer 1

2)
a=mere are Andrei
b=mere are Barbu
c=mere are Calin
a+b+c=22
b=2a
c=b-3
c=2a-3
a+2a+2a-3=22
5a=22+3
5a=25
a=25:5
a=5
b=5*2=10
c=5*2-3=7
3)
$x=(\sqrt{2}+ \sqrt{72}):( \sqrt{18}+ \sqrt{50}- \sqrt{32})= \\ ( \sqrt{98}):( \sqrt{32})= \\ \sqrt{98:32}= \\ \sqrt{3,0625}=1,75$
Raspus final: x=1,75

Answer 2

A+B+C=22 
B=2A
C=B-3=2A-3
in prima ecuatie inlocuim pe B si C
A+2A+2A-3=22
5A=22+3⇒5A=25⇒  A=25:5=5
A=5
B=2A=2×5=10
C=B-3=10-3=7
deci Andrei are 5 mere, Barbu are 10 si Calin 7

3)
[√2+√(72)]:[√(18)+√(50)-√(32)

=[√2+√(2³×3²)]:[√(2×3²)+√(2×5²)-√(2³×2²)

=(√2+2×3√2):(3√2+5√2-4√2)

=7√2:4√2

=7/4
=1,75

4) (12x³-3)/(4x²-4x+1)=3(4x²-1)=3(2x-1)(2x+1)
si numitorul  4x²-4x+1=(2x-1)²2
deci expresia initiala [ 3(2x-1)(2x+1)] /[[(2x-1)²]
se reduc cu (2x-1)

⇒3(2x+1)/(2x-1)