Resolução de questões do livro Matemática Para Concurso - Hilder Góes e Ubaldo Tonar. 6º Edição.

1. 8
EQUAÇÃO DO PRIMEIRO GRAU
8x − 3x = 10  5 5x − 7x = 4 − 8 12
x =
5x = 15 −2x = −4 03 3
01 02
15 4 x =4
x = x =
5 2
x =3 x = 2
6x = 36 2x = −8 3x = 3  6 7x = 28
04 x = 36 05 x = − 8 06 x =
9 07 x = 28
6 2 3 7
x =6 x = −4 x =3 x = 4
3x  x = −9  25 5x − 2x = 4  5
2x = 3
08 3 09 4x = 16 3x = 9
x = 16 10 9
2 x = x =
4 3
x =4 x =3
2x − 4x = 3 − 5
11 −2x = −2 2x − 3x = −4 − 3
2 12 −x = −7
x =
2 x = 7
x = 1
4x − 4 = 2x  8 6x − 15  16 − 4x = 0
4x − 2x = 8  4 6x − 4x = −16  15
13 14
12 2x = −1
2x = 12 2 =
2 1
x =−
x =6 2
2x − 6 = −3x  9
3x − 12 = 0 3x − 4 = 2x  6 2x  3x = 9  6
3x = 12 16 3x − 2x = 6  4 17 5x = 15
15
12 x = 10 15
x = x =
3 5
x =4 x =3
10  6x = 5x  15 6x  6 − 5x − 10 − 6 = 0
18 6x − 5x = 15 − 10 19 6x − 5x = 5x − 6  10  6
x =5 x = 10

2. 7x − 21 = 9x  9 − 38 5x − 15 − 4x − 8 = 1 − 5x
7x − 9x = 9 − 38  21 5x − 4x  5x = 1  15  8
20 −2x = −8 21 6x = 24
8 24
x = x =
2 6
x = 4 x =4
5x  5  6x  12 = 9x  27 20x − 12 − 192  64x − 36x  12 = 96
5x  6x − 9x = 27 − 5 − 12 20x  64x − 36x = 96  12  192 − 12
22 2x = 10 23 48x = 288
10 288
x = x =
2 48
x =5 x =6
10x  50  8x  32 = 5x  65  121 6x − 4x = 6x − 6
10x  8x − 5x = 65  121 − 50 − 32 6x − 4x − 6x = −6
4x = 6
24 13x = 104 25 6
288 x =
x = 4
48
x =8 3
x =
2
2x  2  3x  6 = 48
6x  4x − 3x = 168
2x  3x = 48 − 2 − 6
26 7x = 168
5x = 40 27 168
40 x =
x = 7
5
x = 24
x =8
4x  2x  3x = 72 3x − 10x = −14
9x = 72 7x = 14
28 72 29 14
x = x =
9 7
x =8 x =2
3x  2x = 14  4x 14x  8 − 10x = 15x − 25
3x  2x − 4x = 14 14x − 10x − 15x = − 25 − 8
30 x = 14 31 11x = 33
33
x =
11
8x − 12 − 18x − 48 = 8x − 36 − 3x − 12 x =3
8x − 12 − 18x  48 = 8x − 36 − 3x  12
32 8x − 18x − 8x  3x = −36  12  12 − 48
−15x = −60
60
x =
15
x = 4

3. 144x − 225x  3.240 = 80x − 20 9x  3 − 4x = 60  x − 1
144x − 225x − 80x = −20 − 3.240 9x − 4x − x = 60 − 1 − 3
−161x = −3.220 4x = 56
33 34
3.220 56
x = x =
161 4
x = 20 x = 14
9x − 6 − 24 − 6x = 24x − 28x − 8
9x − 6 − 24  6x = 24x − 28x  8
35 9x  6x − 24x  28x = 8  6  24
19x = 38
38
x =
19
x =2
4x  8 − 3x − 9 = 12x − 24 − 6x − 6
4x  8 − 3x  9 = 12x − 24 − 6x  6
4x − 3x − 12x  6x = −24  6 − 8 − 9
36 −5x = −35
35
x =
5
x = 7