Question

5,6 urgent dau coroana

Answer 1

5) a)

$\frac{a}{b} = 0.75 = \frac{75}{100} = \frac{3}{4} = k$,

$a= 3k$

$b = 4k$

$\frac{2 \cdot 3k - 4k}{3k + 2 \cdot 4k} = \frac{2k}{11k} = \frac{2}{11}$

b)

$\frac{2a-b}{a+2b} = \frac{2}{11}$

$22a-11b=2a+4b$

$20a=16b |:4$

$5a=4b |:5$

$a=\frac{4b}{5} |:b$

$a = \frac{4}{5}$

6)

a) $4 - 3 (2 -5 ) = 4 - 6 - 15 = -17$

b) $-17-\left[\left(5-14\right)\div \left(-3-6\right)-8\right]\cdot \:2 =-17-\left(-7\right)\cdot \:2 =-17-\left(-14\right) =-3$

c) $-3\left[\left(-3\right)^2-5\right]-\left(-2\right)^2 =-3\cdot \:4-\left(-2\right)^2 =-3\cdot \:4-4 =-12-4 = -16$

d) $\left|2^3-3\right|-\left|5-2^3\right| =\left|5\right|-\left|5-2^3\right| =\left|5\right|-\left|-3\right|=$

$\left|5\right| =5$

$\left|-3\right| = 3$

$=5-3 = 2$

Sper ca te-am ajutat!