Question

determine o valor da variável nas equação a)10×-8=3×+6 b)5+2(3y-1)=7y+6 c) 4t-(2t-5)=3-4(2t+3)
alguém pra me ajudar​

Answer 1

Olá!

a) $10x-8=3x+6\quad :\quad x=2$

$10x-8=3x+6$

$10x-8+8=3x+6+8$

$10x=3x+14$

$10x-3x=3x+14-3x$

$7x=14$

$\frac{7x}{7}=\frac{14}{7}$

$x=2$

b) $5+2\left(3y-1\right)=7y+6\quad :\quad y=-3$

$5+2(3y-1)=7y+6$

$5+2\left(3y-1\right)$

$=5+6y-2$

$=6y+3$

$6y+3=7y+6$

$6y+3-3=7y+6-3$

$6y=7y+3$

$6y-7y=7y+3-7y$

$-y=3$

$\frac{-y}{-1}=\frac{3}{-1}$

$y=-3$

c) $4t-\left(2t-5\right)=3-4\left(2t+3\right)\quad :\quad t=-\frac{7}{5}\quad \left(\mathrm{Decimal}:\quad t=-1.4\right)$

$4t-\left(2t-5\right)=3-4\left(2t+3\right)$

$4t-\left(2t-5\right)$

$=4t-2t+5$

$=2t+5$

$3-4\left(2t+3\right)$

$=3-8t-12$

$=-8t-9$

$2t+5=-8t-9$

$2t+5-5=-8t-9-5$

$2t=-8t-14$

$2t+8t=-8t-14+8t$

$10t=-14$

$\frac{10t}{10}=\frac{-14}{10}$

$\frac{10t}{10}$

$=t$

$\frac{-14}{10}$

$=-\frac{14}{10}$

$=-\frac{7}{5}$

$t=-\frac{7}{5}$

Espero ter ajudado!

Bons estudos!

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