Question

resolva as seguintes equações do primeiro grau com uma incógnita:
a)3x - 6 = x
b)5 + 9x = 4x + 15
c)3y + 7 = 2y + 1
d) 2. ( x + 4 ) = x +11

Answer 1

$a)\\3x-6=x\\\\3x-6+6=x+6\\\\3x=x+6\\\\3x-x=x+6-x\\\\2x=6\\\\\frac{2x}{2}=\frac{6}{2}\\\\x=3$

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$b)\\5+9x=4x+15\\\\5+9x-5=4x+15-5\\\\9x=4x+10\\\\9x-4x=4x+10-4x\\\\5x=10\\\\\frac{5x}{5}=\frac{10}{5}\\\\x=2$

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$c)\\3y+7=2y+1\\\\3y+7-7=2y+1-7\\\\3y=2y-6\\\\3y-2y=2y-6-2y\\\\y=-6$

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$d)\\2\left(x+4\right)=x+11\\\\2x+8=x+11\\\\2x+8-8=x+11-8\\\\2x=x+3\\\\2x-x=x+3-x\\\\x=3$