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

1. 16
QUESTÕES DE CONCURSOS
01 4 − 8x  30 − 15x  10 − 10x
−8x − 15x  10x  10 − 4 − 30
−13x  −24
13x  24
24
x
13
02 90x  30 − 390 − 195x = 312x − 78 − 260x − 650
90x  30 − 390  195x = 312x − 78 − 260x  650
90x  195x − 312x  260x = −78  650 − 30  390
233x = 932
x=4
03 65 11
15 15 11 6 11 2 22
= = . = . =
9−2 7 15 7 5 7 35
6 6
04 5x  10a − 7a = 2a  2x
5x − 2x = 2a − 10a  7a
−3x = −a
3x = a
a
x=
3
3,78 378
05 x= ⇒ ⇒ 9,45
0,4 40
06 1 1 32 5 5

2 3 6 6 6 5 6
= = = = . =1
1 1 1 6−1 5 6 5
1− . 1−
2 3 6 6 6
07 −2 − 2  5 = 1
08 0,06 6
= = 0,05
1,2 120
09
 150
3

10
2 
÷
50
1
=  50  5  ÷ 50 =
55
50
= 1,1
10
 1
5
−
25
1.000 
÷
4
100
= 
1
5
−
1
40
÷ 1
25
=
8−1
40 
÷
1
25
= 
7
40
÷  
1
25
=
7 25 7 5 35
. = . =
40 1 8 1 8

2. 150 1 25 1 250 − 1 249
11 − = − = = = 12,45
12 20 2 20 20 20
12 2 ax  y  = 2ax  2y
1.728
13 = 14,4
120
14 15a 10 a 1
 = 
60 90 4 9
3 1 3
15 a=b÷c ⇒ = .
4 2 2
16 2 4 16 − 1 416 − 41 26 − 2 2 99 15 375 24
÷ −2  . = . −2  . =
9 99 90 900 90 9 4 90 900 90
1 11 1 5 4 11 13 5 2 33 − 13 1 1
. −2  . = −  . =  . =
1 2 6 12 15 2 6 12 15 6 6 3
20 1 10 1 60  18 78 39 3
 =  = = = =4
6 18 3 18 18 18 9 9
17 145 − 1 144 24 8
= = =
90 90 15 5
3 1
18 1  16− 
1 17 − 3 14 7
2
= = =
4 4 2
2
1 
19 1 − −1 − 1 − −1  1 − 1 − 1 − 1 = 0
20 x = −8 − 1  9 − 4 = −4
−5  −4  −1
3 2 2 3
21
       
1
2
−3
1
2
. −
1
2
3
1
2
. −
1
2
− −
1
2
=
1
8
−3 −
1
8  
1
3. − −
8
1
8
1 3 3 1 8
 
=    = =1
8 8 8 8 8
[  ]   [  ]
2 2
22 4−1 1 32−4 3 1 1
 ÷ =  ÷ =
6 2 4 6 2 4
 9
36

1
2
1
÷ =
4 9  18
36
1
÷ =
4
27 4
. =
36 1
3 4
. =3
4 1

3. 5
23 0,0525 . 10 = 5.250
24 10 8 . 10−3 10 5
= = 104
10 10
7,8
25 0,52 − 2,5  = 0,25 − 2,5  2,6 = 0,35
3
26 −29
6
= −2 9 − 6 = −23 = −8
−2
−1
 
−1
 
27 1 1 1 2
1 2 . 1
23 22 20 8 4 20
− ÷ = − ÷ =
4 8 9−4 4 8 5
−1
 
18 2
−1 −1
8
4
−
4
8
÷4=  9 1
8 4
2 1
. − .
4 8  .
1
4
= 
9
32
−
1
16  .
1
4
=
−1 −1
 9−2
32  .
1
4
=
7
32  .
1
4
=
32 1
7
. =
4
8
7