`x/5 = -2/(1,25)`
Bài 1: Tính
1) 2,75 - 5/6 × 2/5
2) 1,25 - ( 5/6 - 0,75 ) - 3/5
3) 4/9 × 0,75 + 8/5 + 3,125
4) 1,125 - 4/7 - 0,12
5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5
Bài 2: Tìm x, biết
1) 1,25 × x - 0,75 = 1/3
2) x - 0,25 × 2/9 = 1/6 × 0,5
3) 3,375 × 8/9 - x = 5/6
4) 1,75 × 4/5 + x = 4,5
1) 2,75 - 5/6 × 2/5 = 2,75 - (5/6) × (2/5) = 2,75 - 1/3 = 2,75 - 0,33 = 2,42
2) 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 3/4) - 3/5 = 1,25 - (5/6 - 9/12) - 3/5 = 1,25 - (10/12 - 9/12) - 3/5 = 1,25 - 1/12 - 3/5 = 1,25 - 0,08 - 0,6 = 1,25 - 0,68 = 0,57
3) 4/9 × 0,75 + 8/5 + 3,125 = (4/9) × 0,75 + 8/5 + 3,125 = 0,44 + 8/5 + 3,125 = 0,44 + 1,6 + 3,125 = 0,44 + 4,725 = 5,165
4) 1,125 - 4/7 - 0,12 = 1,125 - (4/7) - 0,12 = 1,125 - 0,57 - 0,12 = 0,435 - 0,12 = 0,315
5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5
x ; 4/5 = 5/2
45,5 ; x = 1,25
\(x:\frac{4}{5}=\frac{5}{2}\)
\(x=\frac{5}{2}×\frac{4}{5}\)
\(x=2\)
vậy x=2
\(45,5:x=1,25\)
x=45,5:1,25
x=36,4
vậy x=36,4
\(x:\frac{4}{5}=\frac{5}{2}\)
\(x=\frac{5}{2}\times\frac{4}{5}\)
\(x=2\)
\(45,5:x=1,25\)
\(x=45,5:1,25\)
\(x=36,4\)
Học tốt
a, x : 4/5 = 5/2
=> x = 5/2 . 4/5
=> x = 20/10
=> x = 2
b, 45,5 : x = 1,25
=> x = 45,5 : 1,25
=> x = 36,4
Timf y :
5 x y + 3,75 x y + 1,25 = 2
\(5\times y+3,75\times y+1,25=2\\ \Rightarrow\left(5+3,75\right)\times y=0,75\\ \Rightarrow8,75\times y=0,75\\ \Rightarrow y=\dfrac{3}{35}\)
12/5-(7/2+x)=1,25
y x 5,3 + y x 1,25 - y x 5 + y x 2 - y = 11,22
y x 5,3+y x 1,25 -y x 5 + y x2 -y x1=11,22 y x(5,3+1,25-5+2-1)=11,22 y x 2,55=11,22 y=11,22 : 2,55 y=...
y x 5,3 + y x 5 + y x 2 - y = 11,22
y x (5,3 + 1,25 - 5 + 2 - 1)=11,22
y x 2,55 =11,22
y = 11,22 : 2,55
y = 4,4
Tính bằng cách thuận tiện nhất:
a) 1,25 x 3,6 + 2,5 x 7,2 x 5 -1,25 x 8 b) 4,16 x 4/5 -80% x 0,16 + 0,96: 1,2
Tính bằng cách thuận tiện nhất:
a) 1,25 x 3,6 + 2,5 x 7,2 x 5 -1,25 x 8
= 1,25 x 4 x 0,9 + 2,5 x 2 x 3,6 x 5 - 1,25 x 4 x 2
= 5 x 0,9 + 5 x 18 - 5 x 2
= 4,5 + 90 - 10
= 84,5
b) 4,16 x 4/5 -80% x 0,16 + 0,96: 1,2
= 4,16 x 0,8 - 0,8 x 0,16 + 0,8
= 0,8 x (4,16 - 0,16 + 1)
= 0,8 x 5 = 4
•2.Biết: x × 1,25 - x : 5 = 15,75. Như vậy, x = ….
x × 1,25 - x : 5 = 15, 75
=> x × 1,25 - x × 1/5 = 15,75
=> x × 1,25 - x × 0,2 = 15,75
=> x × (1,25 - 0,2) = 15,75
=> x × 1,05 = 15,75
=> x = 15,75 : 1,05
=> x = 15
X x1,25 X :5 =15,75
X x 1,25 - X x 0,2 =15,75
X x (1,25 - 0,2 ) =15,75
X x 1,05 =15,75
X =15,75 : 1,05
X =15
1/2 x A + 25% x A + A x 5 + A x 1,25 + A - 28,3 = 36,5
\(A\times\left(\dfrac{1}{2}+25\%+5+1,25+1\right)=36,5+28,3\)
\(A=\dfrac{324}{5}:8=\dfrac{81}{10}\)
1/2 x A + 25% x A + A x 5 + A x 1,25 + A - 28,3 = 36,5
-4/15+2x=1,25 (2,5-x):1/4=-5/2
a: =>2x=5/4+4/15=91/60
=>x=91/120
b: =>2,5-x=-5/2*1/4=-5/8=-0,625
=>x=3,125