Question

Me ajudem nas atividades a seguir

Answer 1

Resposta:

$1)~x+x+1+x+2=393\\ \\ 3x+3=393\\ \\ 3x=393-3\\ \\ 3x=390\\ \\ x=\frac{390}{3} =130\\ \\ x=130\\ x+1=131\\ x+2=132\\ \\ 130+131+132=393\\ \\ Que~numeros~sao~esses?~~~~130,~131,~132$

$2)\\ \\ a)~18x-43=65\\ \\ 18x=65+43\\ \\ 18x=108\\ \\ x=\frac{108}{3} \\ \\ x=36\\ \\ b)~23x-16=14-17x\\ \\ 23x+17x=14+16\\ \\ 40x=30\\ \\ x=\frac{30}{40} =\frac{3}{4} =0,75\\ \\ c)~10y-5(1+y)=3(2y-2)-20\\ \\ 10y-5-5y=6y-6-20\\ \\ 10y-5y-6y=-6-20+5\\ \\ -y=-21~~.(-1)\\ \\ y=21$

$d)~x(x+4)+x(x+2)=2x^{2} +12\\ \\ x^{2} +4x+x^{2} +8=2x^{2} +12\\ \\ x^{2} +x^{2} -2x^{2} +4x=12-8\\ \\ +2x^{2} -2x^{2} +4x=4\\ \\ 4x=4\\ \\ x=\frac{4}{4 } \\ \\ x=1$

$e)\frac{x-5}{10} +\frac{1-2x}{5} =\frac{3-x}{4} \\ \\ m.m.c.=20\\ \\ \frac{2(x-5)+4(1-2x)=5(3-x)}{20} \\ \\ despreze~o~denominador~"20"\\ \\ 2(x-5)+4(1-2x)=5(3-x)\\ \\ 2x-10+4-8x=15-5x\\ \\ 2x-8x+5x=15+10-4\\ \\ -x=21~~.(-1)\\ \\ x=21$

$f)~4x(x+6)-x^{2} =5x^{2} \\ \\ 4x^{2} +24x-x^{2} =5x^{2} \\ \\ 4x^{2} -x^{2} -5x^{2} +24x=0\\ \\ -2x^{2} +24x=0\\ \\ equacao~do~2^{o}~grau~incompleta:c=0\\ \\ x=\frac{-b}{a} \\ \\ x=\frac{-24}{-2} \\ \\ x=12$