• Matéria: Matemática
  • Autor: jennifercbo
  • Perguntado 9 anos atrás

é muito urgente !!!!

Sendo U = Q.

A)  \frac{5x}{4}  - 1 > x -  \frac{5}{8}

b) 0.6 +  \frac{y}{2} \geq   \frac{5}{6} - y

c)  \frac{7x}{6} - 0.25 <  \frac{2x}{3}

d)  \frac{2x-4}{9}<  \frac{4x+1}{3}

e)  \frac{1}{3}  \geq 0.75 (8t- \frac{2}{9})

f)  \frac{3}{5} (3x-2) <  \frac{2}{3} (2x+1)

Preciso de calculos !!!!!!!! 

Respostas

respondido por: fagnerdi
2
Oi Jennifer. Aí estão os cálculos.
a) \frac{5x}{4} -1>x- \frac{5}{8} \\ \\   \frac{10x-8>8x-5}{8}  =10x-8x>-5+8  \\  \\ 2x>3 \\  \\ x>3/2

b) 0.6+ \frac{y}{2}  \geq  \frac{5}{6}-y  \\  \\  \frac{6}{10}+  \frac{y}{2}  \geq  \frac{5}{6}-y  \\  \\  \frac{18+15y \geq 25-30y}{30} =18+15y \geq 25-30y \\  \\ 15y+30y \geq 25-18 \\  \\ 45y \geq 7 \\ y \geq 7/45

c)  \frac{7x}{6} -0.25< \frac{2x}{3}  \\  \\ \frac{7x}{6} - \frac{25}{100} < \frac{2x}{3}  \\  \\  \frac{350x-75<200x}{300}= 350x-75<200x \\  \\ 350x-200x<75 \\ 150x<75 \\ x<75/150 \\ x<0.5

 d)  \frac{1}{3}  \geq 0.75(8t- \frac{2}{9} ) \\  \\  \frac{1}{3}  \geq  \frac{75}{100} (8t- \frac{2}{9} ) \\  \\  \frac{1}{3}  \geq  \frac{600t}{100}- \frac{150}{900} \\  \\  \frac{1}{3} \geq 6t- \frac{1}{6} \\  \\  \frac{2 \geq 36t-1}{6} =2 \geq 36t-1 \\  \\ -36t \geq -1-2 \\  \\ -36t \geq -3 \ \ \ \ *(-1)    \\  \\ 36t \leq 3 \\  \\ t \leq 3/36 \\  \\ t \leq 1/12

e) \frac{2x-4}{9} < \frac{4x+1}{3} \\  \\  \frac{2x-4<3(4x+1)}{9}  = 2x-4<3(4x+1) \\  \\ 2x-4<12x+3 \\  \\ 2x-12x<3+4 \\  \\ -10x<7  \  \  \   \   *(-1) \\  \\ 10x>-7 \\  \\ x>-7/10

f)  \frac{3}{5}(3x-2)< \frac{2}{3}(2x+1) \\  \\  \frac{9x}{5}- \frac{6}{5}  < \frac{4x}{3}+ \frac{2}{3} \\  \\  \frac{27x-18<20x+10}{15}  =    27x-18<20x+10 \\  \\ 27x-20x <10+18 \\ 7x<28 \\ x<28/7 \\ x<4





jennifercbo: Obrigada.
respondido por: MATHSPHIS
2
a)\\
\frac{5x}{4}-1>x-\frac{5}{8}\\
\\
10x-8>8x-5\\
\\
10x-8x>-5+8\\
\\
2x>3\\
\\
x>\frac{3}{2}

b)\\
0,6+\frac{y}{2} \geq \frac{5}{6}-y\\
\\
\frac{6}{10}+\frac{y}{2} \geq \frac{5}{6}-y\\
\\
18+15y \geq 25-30y\\
\\
15y+30y \geq 25-18\\
\\
45y \geq 7\\
\\
y \geq \frac{7}{45}

c) \\
\frac{7x}{6}-0,25<\frac{2x}{3}\\
\\
\frac{7x}{6}-\frac{1}{4}<\frac{2x}{3}\\
\\
14x-3<8x\\
\\
14x-8x<3\\
\\
6x<3\\
\\
x<\frac{1}{2}

d)\\
\frac{2x-4}{9}<\frac{4x+1}{3}\\
\\
2x-4<12x+3\\
\\
2x-12x<3+4\\
\\
-10x<7\\
\\
x>-\frac{7}{10}

e)\\
\frac{1}{3} \geq 0,75(8t-\frac{2}{9})\\
\\
\frac{1}{3} \geq \frac{3}{4}(8t-\frac{2}{9})\\
\\
4 \geq 8t-\frac{2}{9}\\
\\
36 \geq 72t-2\\
\\
38 \geq 72t\\
\\
72t \leq 38\\
\\
t \leq \frac{38}{72}=\frac{19}{36}

f)\\
\frac{3}{5}(3x-2)<\frac{2}{3}(2x+1)\\
\\
9(3x-2)<10(2x+1)\\
\\
27x-18<20x+10\\
\\
27x-20x>10+18\\
\\
7x>28\\
\\
x>4

jennifercbo: Muito obrigada.
fagnerdi: A letra E está errada . A resposta Correta é t<= 1/12
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