Question

resolva as equaçoes
a)7y+5-y+8=31
b)5.(3-2a)=55
c)27=3.9(x+3)
d)16x+2.(7x+8)-9=67
e)6.(4z+2)+7.(5z+3)=66
f)12+(3x+6).(-7)-5=70

Answer 1

$a)\\ 7y+5-y+8=31\\ \\7y -y = 31 - 5 - 8 \\ \\ 6y = 18\\ \\ y = \frac{18}{6}\\ \\ y = 3$

$b) \\ 5*(3-2a)=55\\ \\ 15 - 10a = 55\\ \\ -10a = 55 - 15 \\ \\ -10a = 40 *(-1)\\ \\ 10a = -40 \\ \\ a = \frac{-40}{10}\\ \\ a = -4$

$c)\\ 27=3*9(x+3)\\ 27 = 3 *(9x + 27)\\ \\ 27 = 27x + 81\\ \\ -27x = 81 - 27\\ \\ -27x = 54* (-1) \\ \\ 27x = - 54 \\ x = \frac{-54}{27}\\ \\ x = -2$

$d)\\ 16x+2*(7x+8)-9=67\\ \\ 16x + 14x + 16 - 9 = 67 \\ \\ 30x = 67 - 16 + 9\\ \\30x = 60\\ \\ x = \frac{60}{30}\\ \\ x = 2\\ \\ e)\\6.(4z+2)+7.(5z+3)=66\\ \\ 24z + 12 + 35z + 21 = 66\\ \\ 24z + 35z = 66 -12 -21\\ \\59z = 33\\ \\ z = \frac{33}{59}$

$f)\\ 12+(3x+6).(-7)-5=70\\ \\ 12 - 21x - 42 - 5 = 70\\ \\ -21x = 70 -12 + 42 + 5\\ \\-21x = 105\\ \\ -21x = 105 (-1)\\ \\ 21x = -105\\ \\ x = \frac{-105}{21}\\ \\ x = -5$