(x+6)*(x-32)<0
x bang bao nhieu?
Cho m= 3/5 x (6/7 x 8/9 x 10/11 x ... x 32/33) và N = 5/6 x 7/8 x 9/10 x ... x 31/32
đề bài là làm gì vậy bạn?
Tính m x n nhé bạn
tính : 7 x 7 x 6 + 6 x 32 + 6 x 33 + 6 x 34 = ?
7 x 7 x 6 + 6 x 32 + 6 x 33 + 6 x 34
= 49 x 6 + 192 + 198 + 204
= 294 + 192 + 198 + 204
= 888
Mk đầu tiên nha
7 x 7 x 6 + 6 x 32 + 6 x 33 + 6 x 34
= (7 x 7 x 6) + 6 x 32 + 6 x 33 + 6 x 34
= 294 + (6 x 32) + (6 x 33) + (6 x 34)
= 294 + 192 + 198 + 204
= 486 + 198 + 204
= 684 + 204
= 888
Tính nhẩm:
8 x 5 =
8 x 4 =
8 x 6 =
8 x 3 =
40 : 8 =
32 : 8 =
48 : 8 =
24 : 8 =
40 : 5 =
32 : 4 =
48 : 6 =
24 : 3 =
Học sinh nhẩm và ghi:
8 x 5 = 40
8 x 4 = 32
8 x 6 = 48
8 x 3 = 24
40 : 8 = 5
32 : 8 = 4
48 : 8 = 6
24 : 8 = 3
40 : 5 = 8
32 : 4 = 8
48 : 6 = 8
24 : 3 = 8
(chú ý: mối quan hệ giữa nhân và chia)
Tính nhẩm:
8 x 5 = 40
8 x 4 = 32
8 x 6 = 48
8 x 3 = 24
40 : 8 = 5
32 : 8 = 4
48 : 8 = 6
24 : 8 = 3
40 : 5 = 8
32 : 4 = 8
48 : 6 = 8
24 : 3 = 8
Tính nhanh 6 x 38 + 6 x 32 + 6
\(6.38+6.32+6=6.\left(38+32+1\right)=6.70=420\)
Tìm số nguyên x, biết
a) x – 2 = -6
b)15 – (x – 7) = -21
c)4.(3x – 4) – 2 = 18
d) (3x – 6) + 3 = 32
e) (3x – 6) . 3 = 32
f) (3x – 6) : 3 = 32
g) (3x – 6) - 3 = 32
h) (3x -2 mũ4 ).7mũ3 = 2.7mũ4
i) |x| = |-7| k) |x+1| = 2
l)|x – 2| = 3
m) x +|-2| = 0
o) 72 – 3.|x + 1| = 9
p) |x+1| = 3 và x+1< 0
q) (x – 2).(x + 4) = 0
a) \(x-2=-6\)
\(x=-6+2\)
\(x=-4\)
b) \(15-\left(x-7\right)=-21\)
\(x-7=36\)
\(x=43\)
c) \(4.\left(3x-4\right)-2=18\)
\(4\left(3x-4\right)=20\)
\(3x-4=5\)
\(3x=9\)
\(x=3\)
d) \(\left(3x-6\right)+3=32\)
\(3x-6=29\)
\(3x=29+6\)
\(3x=35\)
\(x=\frac{35}{3}\)
e) \(\left(3x-6\right).3=32\)
\(3x-6=\frac{32}{3}\)
\(3x=\frac{32}{3}+6\)
\(3x=\frac{50}{3}\)
\(x=\frac{50}{9}\)
f) \(\left(3x-6\right):3=32\)
\(3x-6=96\)
\(3x=102\)
\(x=34\)
g) \(\left(3x-6\right)-3=32\)
\(3x-6=35\)
\(3x=41\)
\(x=\frac{41}{3}\)
h) \(\left(3x-2^4\right).7^3=2.7^4\)
\(\left(3x-2^4\right)=2.7=14\)
\(\left(3x-16\right)=14\)
\(3x=14+16=30\)
\(x=10\)
i) \(\left|x\right|=\left|-7\right|\)
\(\left|x\right|=7\)
\(\Rightarrow\orbr{\begin{cases}x=7\\x=-7\end{cases}}\)
k) \(\left|x+1\right|=2\)
\(\Rightarrow\orbr{\begin{cases}x+1=2\\x+1=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-3\end{cases}}}\)
l) \(\left|x-2\right|=3\)
\(\Rightarrow\orbr{\begin{cases}x-2=3\\x-2=-3\end{cases}\Rightarrow\orbr{\begin{cases}x=5\\x=-1\end{cases}}}\)
m) \(x+\left|-2\right|=0\)
\(x+2=0\)
\(x=-2\)
o) \(72-3\left|x+1\right|=9\)
\(3\left|x-1\right|=63\)
\(\left|x-1\right|=21\)
\(\Rightarrow\orbr{\begin{cases}x-1=21\\x-1=-21\end{cases}\Rightarrow\orbr{\begin{cases}x=22\\x=-20\end{cases}}}\)
p) Ta có: \(\left|x-1\right|=3\)
\(\Rightarrow\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}}\)
mà \(x+1< 0\)
\(\Rightarrow x-1=-3\)
\(\Rightarrow x=-2\)
q) \(\left(x-2\right)\left(x+4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-2=0\\x+4=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2\\x=-4\end{cases}}}\)
hok tốt!!
cho biểu thức với m = 6,44 phẩy 8 x 1230 + 6 x 4567 x 8 + 531 x 240 x 2 phần 12 x x 8 + 16 x m x 6 + 24 x m x 4 + 32 x m x 3 + 32 x m x 3 + m x 96
1. x - 8 +32= 68
2. x +8+32=68
3. 98-x +34=43
4. 98+x-34=43
5. x :5:4=800
6. 18+x=384:8
7. (84,6-2 x x):3,02= 5,1
8. x x5= 120:6
9. (15x 24-x) :0,25= 100:0,25
1. \(x-8+32=68\)
\(x-8=68-32\)
\(x-8=36\)
\(x=36+8\)
\(x=44\)
_____
2. \(x+8+32=68\)
\(x+8=68-32\)
\(x+8=36\)
\(x=36-8\)
\(x=28\)
_____
3. \(98-x+34=43\)
\(98-x=43-34\)
\(98-x=9\)
\(x=98-9\)
\(x=89\)
_____
4. \(98+x-34=43\)
\(98+x=43+34\)
\(98+x=77\)
\(x=77-98\)
\(x=-21\)
_____
5. \(x:5:4=800\)
\(x:5=800.4\)
\(x:5=3200\)
\(x=3200.5\)
\(x=16000\)
_____
6. \(18+x=384:8\)
\(18+x=48\)
\(x=48-18\)
\(x=30\)
_____
7. \(\left(84,6-2\times x\right):3,02=5,1\)
\(84,6-2.x=5,1.3,02\)
\(84,6-2.x=15,402\)
\(2.x=84,6-15,402\)
\(2.x=69,198\)
\(x=69,198:2\)
\(x=34,599\)
_____
8. \(x\times5=120:6\)
\(x.5=20\)
\(x=20:5\)
\(x=4\)
_____
9. \(\left(15\times24-x\right):0,25=100:0,25\)
\(\left(15.24-x\right):0,25=400\)
\(15.24-x=400.0,25\)
\(15.24-x=100\)
\(360-x=100\)
\(x=360-100\)
\(x=260\)
1,x-8+32=68
=>x-8=68-32=36
=>x=36+8=42
2,x+8+32=68
=>x+8=68-32=36
=>x=36-8=28
3,98-x+34=43
=>98-x=43-34=9
=>x=98-9=89
4,98+x-34=43
=>98+x=43+34=77
=>x=77-98=-21
5,x:5:4=800
=>x:20=800
=>x=800x20=16000
6,18+x=384:8=48
=>x=48-18=30
7,(84,6-2x):3,02=5,1
=>84,6-2x=5,1x3,02=15,402
=>2x=84,6-15,402=69,198
=>x=69,198:2=34,599
8,5x=120:6=20
=>x=20:5=4
9,(15x24-x):0,25=100:0,25=400
=>360-x=400x0,25=100
=>x=360-100=260.
1. \(...\Rightarrow x+24=68\Rightarrow x=68-24=44\)
2. \(...\Rightarrow x+40=68\Rightarrow x=68-40=28\)
3. \(...\Rightarrow3^{2\left(8+x\right)}=9=3^2\Rightarrow2\left(8+x\right)=2\Rightarrow8+x=1\Rightarrow x=-7\)
4. \(...\Rightarrow3^{2\left(8+x\right)}=77\) (bạn xem lại đề)
5. \(...\Rightarrow x:5=800.4\Rightarrow x:5=3200\Rightarrow x=3200.5=16000\)
6. \(...\Rightarrow18+x=48\Rightarrow x=48-18=30\)
7. \(...\Rightarrow84,6-2x=5,1.3,02=15,402\Rightarrow2x=84,6-15,402\Rightarrow2x=69,198\Rightarrow x=34,599\)
8. \(...\Rightarrow5.x=20\Rightarrow x=20:5=4\)
9. \(\left(360-x\right):0,25=400\Rightarrow360-x=400.0,25=100\Rightarrow x=400-100=300\)
1. Tìm x biết: (x +2) + (x+4)+(x +6) +….+ (x+32) =352
(x+2)+(x+4)+(x+6)+...+(x+32)=352(x+2)+(x+4)+(x+6)+...+(x+32)=352
(x+x+...+x)+(2+4+6+...+32)=352(x+x+...+x)+(2+4+6+...+32)=352
16x+272=35216x+272=352
16x=352−272=8016x=352−272=80
x=80:16=5
Đúng ghi Đ, sai ghi S:
a) 32 : 4 : 2 = 8 : 2 = 4
32 : 4 : 2 = 32 : 2 = 16
b) 18 : 2 x 3 = 18 : 6 = 3
18 : 2 x 3 = 9 x 3 = 18
a) 32 : 4 : 2 = 8 : 2 = 4
32 : 4 : 2 = 32 : 2 = 16
b) 18 : 2 x 3 = 18 : 6 = 3
18 : 2 x 3 = 9 x 3 = 18