35 x 50 + 35 x 49 + 35
tính bằng cách thuận lợi nhất
35 x 50 + 35 x 49 + 35 =
35 x ( 50 + 49 + 1 )
= 35 x 100
= 3500
gửi kb cho tớ nhé
35*50+35*49+35
=35*50+35*49+35*1
=35*(50+49+1)
=35*100
=3500
Tk nha
=35x50+35x{49+1}
=35x50+35x50
=35x{50+50}
=35x100
=3500
tính bằng cách thuận tiện nhất / 35 x 50 - 35 x 49 + 3
35 x 50 - 35 x 49 + 3
= 36 x (50 + 49) + 3
= 36 x 99 + 3
= 3564 + 3
= 3567
35 x 50 - 35 x 49 + 3
=35x(50-49)+3
=35x1+3
=35+3
=38
35 x 50 - 35 x 49 + 3
= 35 x ( 50 - 49 ) + 3
= 35 x 1 + 3
= 35 + 3
= 38
Tính bằng cách thuận lợi nhất. 35 × 50 + 35 × 49 + 35
35 × 50 + 35 × 49 + 35 = 35 x ( 50 + 49 + 1) = 35 x 100 = 3500
Giải các phương trình sau:
9) x-49/ 50 + x-50/ 49 = 49/ x-50 + 50/ x-49
7) x+25/ 75 + x+30/70 = x+35/65 + x+40/60
8) 99-x/101 + 97-x/103 + 95-x/105 + 93-x/107 = 4
10) x+14/86 + x+15/85 + x+16/84 + x+17/83 + x+116/4 = 0
7) \(\frac{x+25}{75}+\frac{x+30}{70}=\frac{x+35}{65}+\frac{x+40}{60}\)
\(\Leftrightarrow\)\(\frac{x+25}{75}+1+\frac{x+30}{70}+1=\frac{x+36}{65}+1+\frac{x+40}{60}+1\)
\(\Leftrightarrow\)\(\frac{x+100}{75}+\frac{x+100}{70}=\frac{x+100}{65}+\frac{x+100}{60}\)
\(\Leftrightarrow\)\(\left(x+100\right)\left(\frac{1}{75}+\frac{1}{70}-\frac{1}{65}-\frac{1}{60}\right)=0\)
\(\Leftrightarrow\)\(x+100=0\) (vì 1/75 + 1/70 - 1/65 - 1/60 \(\ne\)0)
\(\Leftrightarrow\)\(x=-100\)
Vậy.....
Giải các phương trình sau:
9) x-49/ 50 + x-50/ 49 = 49/ x-50 + 50/ x-49
7) x+25/ 75 + x+30/70 = x+35/65 + x+40/60
8) 99-x/101 + 97-x/103 + 95-x/105 + 93-x/107 = 4
10) x+14/86 + x+15/85 + x+16/84 + x+17/83 + x+116/4 = 0
7) \(\frac{x+25}{75}+\frac{x+30}{70}=\frac{x+35}{65}+\frac{x+40}{60}\)
\(\Leftrightarrow\)\(\frac{x+25}{75}+1+\frac{x+30}{70}+1=\frac{x+35}{65}+1+\frac{x+40}{60}+1\)
\(\Leftrightarrow\)\(\frac{x+100}{75}+\frac{x+100}{70}=\frac{x+100}{65}+\frac{x+100}{60}\)
\(\Leftrightarrow\)\(\left(x+100\right)\left(\frac{1}{75}+\frac{1}{70}-\frac{1}{65}-\frac{1}{60}\right)=0\)
\(\Leftrightarrow\)\(x+100=0\) (1/75 + 1/70 - 1/65 - 1/60 \(\ne\)0)
\(\Leftrightarrow\)\(x=-100\)
Vậy...
1/2×(2×x-3)+105/2=-137/2 A,-12×25-25×75-25×13 B,-50/7×49/10-35/2×-10/7+ -25/3× -9/5 C,-354+265-156+125 D,-74+40-50+16-35 E,-2/3×4/5+-4/5×4/3-0,125
1/2×(2×x-3)+105/2=-137/2
1/2×(2×x-3)=-137/2-105/2
1/2×(2×x-3)=-242/2
2×x-3=-242/2:1/2
2×x-3=-242
2.x=(-242)+3
2.x=239
x=239:2
x=239/2
A,-12×25-25×75-25×13
=[(-12)-75-13].25
=(-100).25
-2500
B,-50/7×49/10-35/2×-10/7+ -25/3× -9/5
=(-35)-(-25)+(-13)
=-23
C,-354+265-156+125
=[(-354)-156]+(265+125)
=(-510)+277
=-233
D,-74+40-50+16-35
=(-74)+40+(-50)+16+(-35)
=[(-74)+(-35)]+[40+(-50)+16]
=(-109)+26
=-83
E,-2/3×4/5+-4/5×4/3-0,125
=-2/3.4/5+4/5.(-4/3)-0,125
=4/5.[-2/3+(-4/3)]-0,125
=4/5.(-2)-0,125
=-8/5-0,125
=(-1,6)+(-0,125)
=-1,725
Tìm x,biết
a) x : 2/3 = 150
b) 35/9 : x = 35/6
c) x : 4/7 = 180
d) 49/8 : x = 49/5
a) \(x:\frac{2}{3}=150\)
\(x=150.\frac{2}{3}\)
\(x=100\)
b) \(\frac{35}{9}:x=\frac{35}{6}\)
\(x=\frac{35}{9}.\frac{6}{35}=\frac{2}{3}\)
c,d tương tự
a ) x : 2/3 = 150 c ) x : 4/7 = 180
x = 150 x 2/3 x = 180 x 4/7
x = 100 x = 720/7
b ) 35/9 : x = 35/6 d ) 49/8 : x = 49/5
x = 35/9 : 35/6 x = 49/8 : 49/5
x = 2/3 x = 5/8
a) x : \(\frac{2}{3}\)= 150
x = 150 x \(\frac{2}{3}\)
x = 100
b) \(\frac{35}{9}:x=\frac{35}{6}\)
x = \(\frac{35}{9}\): \(\frac{35}{6}\)
x = \(\frac{2}{3}\)
c) x : 4/7 = 180
x = 180 x 4/7
x = 720/7
d) 49/8 : x = 49/5
x = 49/8 : 49/5
x = 5/8
nhớ k cho mik nha mik đang rất cần cái k của bn
Giải các phương trình sau:
9) x-49/ 50 + x-50/ 49 = 49/ x-50 + 50/ x-49
7) x+25/ 75 + x+30/70 = x+35/65 + x+40/60
8) 99-x/101 + 97-x/103 + 95-x/105 + 93-x/107 = 4
10) x+14/86 + x+15/85 + x+16/84 + x+17/83 + x+116/4 = 0
9: \(\dfrac{x-49}{50}+\dfrac{x-50}{49}=\dfrac{49}{x-50}+\dfrac{50}{x-49}\)
=>x-99=0
hay x=99
7: \(\Leftrightarrow\left(\dfrac{x+25}{75}+1\right)+\left(\dfrac{x+30}{70}+1\right)=\left(\dfrac{x+35}{65}+1\right)+\left(\dfrac{x+40}{60}+1\right)\)
=>x+100=0
hay x=-100
8:
Sửa đề: \(\dfrac{99-x}{101}+\dfrac{97-x}{103}+\dfrac{95-x}{105}+\dfrac{93-x}{107}=-4\)
\(\Leftrightarrow\left(\dfrac{99-x}{101}+1\right)+\left(\dfrac{97-x}{103}+1\right)+\left(\dfrac{95-x}{105}+1\right)+\left(\dfrac{93-x}{107}+1\right)=0\)
=>200-x=0
hay x=200
tính bằng cách hợp lí
a) 37 . 49 + 49 . 60 + 3 . 49
b) 36 . 42 - 62 . 5 + 63 . 62
c) 35 x 21 + 35 x 80 - 35
1 + 4 + 7 +...+ 16 + 19
a) 37.49+49.60+3.49
(37+60+3).49
100.49
4900
b; 36. 42 - 62.5 + 63 .62
= 36.42 - 36.5 + 63.36
= 36.(42 - 5 + 63)
= 36.100
= 3600
c; 35 x 21 + 35 x 80 - 35
= 35 x (21 + 80 - 1)
= 35 x 100
= 3500