x + 70 = 40 x 2
Tính nhẩm:
a) 10 x 7 20 x 4 40 x 2 30 x 3
b) 60 : 2 90 : 3 70 : 7 40 : 2
a) 10 x 7 = ? Nhẩm: 1 chục x 7 = 7 chục 10 x 7 = 70 20 x 4 = ? Nhẩm: 2 chục x 4 = 8 chục 20 x 4 = 80 40 x 2 = ? Nhẩm: 4 chục x 2 = 8 chục 40 x 2 = 80 30 x 3 = ? Nhẩm: 3 chục x 3 = 9 chục 30 x 3 = 90 | b) 60 : 2 = ? Nhẩm: 6 chục : 2 = 3 chục 60 : 2 = 30 90 : 3 = ? Nhẩm: 9 chục : 3 = 3 chục 90 : 3 = 30 70 : 7 = ? Nhẩm: 7 chục : 7 = 1 chục 70 : 7 = 10 40 : 2 = ? Nhẩm: 4 chục : 2 = 2 chục 40 : 2 = 20 |
40 + 30 + 50 + 70 + 8 + 65 + 12 + 30 +40 + 5 x 2 + 21 x 23 = ?
(35.15):2=(x+70):14-40
525:2=(x+70):14-40
262,5=(x+70):14-40
Ta có:(x+70):14-40=262,5
(x+70):14 =262,5+40
(x+70):14 =302,5
x+70 =302,5*14
x+70 =4235
x+70
( 35 . 15 ) : 2 = ( x + 70 ) : 14 - 40
525 : 2 = ( x + 70 ) : 14 - 40
262, 5 = ( x + 70 ) : 14 - 40
( x + 70 ) : 14 - 40 = 262, 5
( x + 70 ) : 14 = 262, 5 + 40
( x + 70 ) : 14 = 302, 5
( x + 70 ) = 302, 5 x 14
( x + 70 ) = 4235
x = 4235 - 70
x = 4165
( 32*15 ) :2=( x +70 ):14 -40
\(\left(32.15\right):2=\left(x+70\right):14-40\)
\(480:2=\left(x+70\right):14-40\)
\(240=\left(x+70\right):14-40\)
\(240-40=\left(x+70\right):14\)
\(200=\left(x+70\right):14\)
\(200.14=x+70\)
\(2800=x+70\)
\(2800-70=x\)
\(2730=x\)
(32.15) : 2 = (x+70) : 14 - 40
\(\left(32\cdot15\right):2=\left(x+70\right):14-40\)
\(=240=\left(x+70\right):14-40\)
\(\Rightarrow\left(x+70\right):14=240+40\)
\(\Rightarrow x+70=280\cdot14\)
\(\Rightarrow x=3920-70\)
\(\Rightarrow x=3850\)
Ủng hộ mk nkoa!@^_^@
(32.15):2=(x+70):14-40
=>(x+70):14-40=480:2=240
=>(x+70):14=240+40=280
=>x+70=280x14=3920
=>x=3920-70=3850
(32 . 15) : 2 = (x + 70) : 14 - 40
480 : 2 = (x + 70) : 14 - 40
240 = (x + 70) : 14 - 40
(x + 70) : 14 = 280
x + 70 = 280 x 14 = 3920
x = 3920 - 70 = 3850
Đúng ghi Đ, sai ghi S:
a) 86 – 16 = 70
b) 23 x 2 – 1 = 23
c) 250 : 5 + 5 = 25
d) 40 + 80 : 4 = 30
e) 80 + 4 : 2 = 42
f) 70 + 30 : 2 = 50
g) 90 + 30 x 3 = 180
h) 70 + 30 : 2 = 85
a) 86 – 16 = 70
b) 23 x 2 – 1 = 23
c) 250 : 5 + 5 = 25
d) 40 + 80 : 4 = 30
e) 80 + 4 : 2 = 42
f) 70 + 30 : 2 = 50
g) 90 + 30 x 3 = 180
h) 70 + 30 : 2 = 85
(32.15):2=(x+70):14-40
(32.15):2=(x+70):14-40
=>480:2=(x+70):14-40
=>240=(x+70):14-40
=>(x+70):14=240+40
=>(x+70):14=280
=>x+70=280*14
=>x+70=3920
=>x=3850
Tìm x biết:
A)195-x:17=125
B) 32.15:2=(x+70):14-40
a) 195 - x: 17 = 125
x : 17 = 195 - 125 = 70
x = 70 . 17
x = 1190
b) 32 . 15 : 2 = (x + 70) : 14 - 40
240 = ( x + 70) : 14 - 40
(x + 70) : 14 = 280
x + 70 = 280 . 14 = 3920
x = 3920 - 70
x = 3850
A)195-x:17=125
=\(x:17=195-125\)
\(x:17=70\)
\(x=70.17\)
=>x=\(1190\)
B) 32.15:2=(x+70):14-40
\(\text{B) 32.15:2=(x+70):14-40}\)
\(=480:2=\left(x+70\right):14-40\)
\(=\left(x+70\right):14-40=240\)
\(=\left(x+70\right):14=240+40\)
\(\left(x+70\right):14=280\)
=>\(x+70=280.14\)
\(x+70=3920\)
=> x=\(3920-70\)
=>x=\(3850\)
a) 195 - x : 7 = 125
x : 7 = 195 - 125
x : 7 = 70
x = 70 x 7
x = 140.
b) 32 x 15 : 2 = ( x + 70 ) : 14 - 40
480 : 2 = ( x + 70 ) : 14 - 40
240 = ( x + 70 ) : 14 - 40
( x + 70 ) : 14 - 40 = 240
( x + 70 ) : 14 = 240 - 40
( x + 70 ) : 14 = 200
x + 70 = 200 x 14
x + 70 = 2800
x = 2800 - 70
x = 2100.
(x+20):(x-10)=(x+40):(x+70)
\(\frac{x+20}{x-10}=\frac{x+40}{x+70}\)
\(\Rightarrow\left(x+20\right)\left(x+70\right)=\left(x+40\right)\left(x-10\right)\)
\(x^2+20x+70x+1400=x^2+40x-10x-400\)
\(90x+1400=30x-400\)
\(60x=-1800\)
\(x=-30\)