5) a)
[tex]\frac{a}{b} = 0.75 = \frac{75}{100} = \frac{3}{4} = k[/tex],
[tex]a= 3k[/tex]
[tex]b = 4k[/tex]
[tex]\frac{2 \cdot 3k - 4k}{3k + 2 \cdot 4k} = \frac{2k}{11k} = \frac{2}{11}[/tex]
b)
[tex]\frac{2a-b}{a+2b} = \frac{2}{11}[/tex]
[tex]22a-11b=2a+4b[/tex]
[tex]20a=16b |:4[/tex]
[tex]5a=4b |:5[/tex]
[tex]a=\frac{4b}{5} |:b[/tex]
[tex]a = \frac{4}{5}[/tex]
6)
a) [tex]4 - 3 (2 -5 ) = 4 - 6 - 15 = -17[/tex]
b) [tex]-17-\left[\left(5-14\right)\div \left(-3-6\right)-8\right]\cdot \:2 =-17-\left(-7\right)\cdot \:2 =-17-\left(-14\right) =-3[/tex]
c) [tex]-3\left[\left(-3\right)^2-5\right]-\left(-2\right)^2 =-3\cdot \:4-\left(-2\right)^2 =-3\cdot \:4-4 =-12-4 = -16[/tex]
d) [tex]\left|2^3-3\right|-\left|5-2^3\right| =\left|5\right|-\left|5-2^3\right| =\left|5\right|-\left|-3\right|=[/tex]
[tex]\left|5\right| =5[/tex]
[tex]\left|-3\right| = 3[/tex]
[tex]=5-3 = 2[/tex]
Sper ca te-am ajutat!
