1. Colégio estadual Dinah Gonçalves
Professor Antonio Carlos Carneiro Barroso
Equações fracionárias
Série 7ª ou 8º ano
accbarroso@hotmail.com
HTTP://ensinodematemtica.blogspot.com
HTTP://accbarroso60.wordpress.com
Atividade para 7ª série
ou 8º ano
Resolva:
x−2 x−3 3
a) + =
4 2 2
3( x − 2 ) 6( x − 3) 18
+ =
12 12 12
3x-6 +6x-18=18
3x+6x-6-18=18
9x=18+18+6
9x=42
42
X=
9
x −1 x − 5 3
+ =
2 3 6
b) 3( x − 1) + 2( x − 5) = 3 mmc 6
6 6 6
3x-3+2x-10=3
3x+2x-3-10=3
5x=3+10+3
5x=16
16
X=
5

2. x−2 x−5 5
+ =
8 3 2
c) 3( x − 2) 8( x − 5) 60 mmc 8,3,2=24
+ =
24 24 24
3x-6+8x-40=60
3x+8x-6-40=60
11x=60+6+40
11x=106
106
X=
11
2 x − 3 3x − 4 5
+ =
2 8 4
4( 2 x − 3) 1( 3 x − 4 ) 10
+ =
8 8 8
8 x − 12 + 3 x − 4 = 10
d) 8 x + 3x − 12 − 4 = 10
11x = 10 + 4 + 12
11x = 26
26
x=
11
x − 5 x −1 4 5( x − 5) + 2( x − 1) = 4
e) + = mmc 10 /5x-25+2x-2=4
2 5 10 10
31
5x+2x=4+25+2 / 7x=31 / x=
7
x−7 x−4 7 4( x − 7 ) + 3( x − 4 ) = 42
f) + = mmc 24 / 4x-28+3x-12=42 /
6 8 4 24
82
4x+3x=42+12+28 /7x=82 / x=
7
x−2 x−4 5 2( x − 2) + 6( x − 4 ) = 45
g) + = mmc 18 / 2x-4+6x-24=45 /
9 3 2 18
73
2x+6x=45+24+4 /8x=73 / x=
8

3. 2x − 1 2x − 3 5 2( 2 x − 1) + 4( 2 x − 3) = 15
h) + = mmc 24 /
12 6 8 24
29
4x-2+8x-12=15 /4x+8x=15+12+2 /12x=29 /x=
12
3x − 4 2 x − 1 5 4( 3x − 4 ) + 7( 2 x − 1) = 70
i) + = mmc 28 /
7 4 2 28
93
12x-16+14x-7=70 /12x+14x =70+7+16 / 26x= 93 / x=
26
x−4 x−3 5 8( x − 4 ) + 9( x − 3) = 90
j) + = mmc 72 /
9 8 4 72
149
8x-32+9x-27=90 /8x+9x=90+27+32 / 17x =149 / x =
17
x−7 x−4 3 8( x − 7 ) + 5( x − 4) = 30
j) + = mmc 40 / 8x
5 8 4 40
-56+5x-20=30 / 8x+5x = 30+20+56 / 13x =106
106
/x=
13
x−2 x−3 3 2( x − 2) + 8( x − 3) = 3
l) + = /mmc=16 / / 2x-4+8x-24
8 2 16 16
=3 /2x+8x =3+4+24 /10x=31
31
x=
10
2 x − 1 3x − 2 8 5( 2 x − 1) + 4( 3 x − 2 ) = 80
m) + = mmc=20 / /
4 5 2 20
10x-5+12x-8=80
93
10x+12x=80+8+5 / 22x=93 /x=
22
2( x − 1) 3( x − 4) 5 8( x − 1) + 30( x − 4 ) = 5
n) + = / mmc=20 / /
5 2 20 20
8x-8+30x-120=5
133
8x+30x=5+120+8 / 38x=133 / x=
38
2 x + 1 3x + 4 3 8( 2 x + 1) + 5( 3x + 4 ) = 60
o) + = / mmc40 / /
5 8 2 40
16x+8+15x+20=60

4. 32
16x+15x=60-20-8 /31x=32 / x=
31
x−5 x−2 7 4( x − 5) − 3( x − 2) = 42
p) − = / mmc 12 / /
3 4 2 12
4x-20-3x+6=42
4x-3x=42-6+20 / x=56
2− x x−5 4 4( 2 − x ) + 6( x − 5) = 12
q) + = / mmc 24 / /
6 4 8 24
8-4x+6x-30=12
-4x+6x=12+30-8 / 2x = 34 / x=34:2 / x= 17