Question

Resolva as equações de 1 grau:

A) 7 ( x - 1 ) -2 ( x - 5 ) = x - 5


B) ( 5 - x ) - 3 ( 1 - 2 x ) = 42


C) 5 ( x - 3 ) - 4 ( x + 2 ) = 2 + 3 ( 1 - 2 x )

Answer 1

Resposta:

$a) \: 7 \times (x - 1) - 2 \times (x - 5) = x - 5 \\ 7x - 7 - 2x + 10 = x - 5 \\ 5x + 3 = x - 5 \\ 5x + 3 - x = - 5 \\ 3x - x = - 5 - 3 \\ 2x = - 8 \div (2) \\ x = - 4$

$b) \: (5 - x) - 3 \times (1 - 2x) = 42 \\ 5 - x - 3 + 6x = 42 \\ 2 + 5x = 42 \\ 5x = 42 - 2 \\ 5x = 40 \div (5) \\ x = 8$

$c) \: 5 \times (x - 3) - 4 \times (x + 2) = 2 + 3 \times (1 - 2x) \\ 5x - 15 - 4x - 8 = 2 + 3 - 6x \\ x - 23 = 5 - 6x \\ x - 23 + 6x = 5 \\ x + 6x = 5 + 23 \\ 7x = 28 \div (7) \\ x = 4$