tính
( + 12 ) x 16 + 16 x ( - 22 )
tính
5/8 x 16 /7 x 21/25
11/12 : 22/30 x 6 /15
5/8x16/7x21/25
=1/1x2/1x3/5
=6/5
11/12:22/30x6/15
=11/12x30/22x6/15
=1/2x1/2x1/2
=1/8
5/8x16/7x21/25
=1/1x2/1x3/5
=6/5
11/12:22/30x6/15
=11/12x30/22x6/15
=1/2x1/2x1/2
=1/8
Tính nhanh:
a,104 x 125 b, 22 x 45 c,50 x 12 d, 250 x 16
104 \(\times\) 125
= 13 \(\times\) 8 \(\times\) 125
= 13 \(\times\) (8 \(\times\) 125)
= 13 \(\times\) 1000
= 13 000
b, 22 \(\times\) 45
= 2 \(\times\) 11 \(\times\) 5 \(\times\) 9
= (2 \(\times\) 5) \(\times\) (11 \(\times\) 9)
= 10 \(\times\) 99
= 990
c, 50 \(\times\) 12
= 50 \(\times\) 2 \(\times\) 6
= 100 \(\times\) 6
= 600
d, 250 \(\times\) 16
= 250 \(\times\) 4 \(\times\) 4
= 1000 \(\times\) 4
= 4000
Giải các phương trình sau:
a) 2 x + 1 2 − x + 2 2 + 3 x 1 − x = 0 ;
b) 2 7 x − 1 6 + 2 x = 1 − 2 x 7 x − 1 6 + 2 x .
12-x=3-22
làm theo quy tac chuyển vế
x+17=-16+11
x+7-8=16-(-7)
(-12)-(13-x)=-15-(-17)
26⋮XVA X≥13
16⋮X vaX<8
18⋮va 0<X<40
X⋮15 va 40 <x<30
x ⋮12 va 22≤5 x<50
x⋮4 va 16 ≤x ≤36
giup minh voi
\(\left\{{}\begin{matrix}26⋮x\\x\ge13\end{matrix}\right.\Rightarrow x\in\left\{13;26\right\}\)
\(\left\{{}\begin{matrix}16⋮x\\x< 8\end{matrix}\right.\Rightarrow x\in\left\{1;2;4\right\}\)
\(\left\{{}\begin{matrix}18⋮x\\0< x< 40\end{matrix}\right.\Rightarrow x\in\left\{1;2;3;6;9;18\right\}\)
\(\left\{{}\begin{matrix}x⋮15\\30< x< 40\end{matrix}\right.\Rightarrow x\in\varnothing\)
\(\left\{{}\begin{matrix}x⋮12\\22\le5x\le50\end{matrix}\right.\Rightarrow x\in\varnothing\)
\(\left\{{}\begin{matrix}x⋮4\\16\le x\le36\end{matrix}\right.\Rightarrow x\in\left\{16;20;24;28;32;36\right\}\)
tìm x biết a, x + 22/11 + x + 23/12 = x + 24/13 + x + 25/14
b, x - 17/16 + x-16/17 = x-15/18 + x-14/19
\(\frac{x+22}{11}+\frac{x+23}{12}=\frac{x+24}{13}+\frac{x+25}{14}\)
\(\Leftrightarrow\left(\frac{x+22}{11}+1\right)+\left(\frac{x+23}{12}+1\right)=\left(\frac{x+24}{13}+1\right)+\left(\frac{x+25}{14}+1\right)\)
\(\Leftrightarrow\frac{x+33}{11}+\frac{x+35}{12}=\frac{x+37}{13}+\frac{x+39}{14}\)
\(\Leftrightarrow\frac{x+33}{11}+\frac{x+35}{12}-\frac{x+37}{13}-\frac{x+39}{14}=0\)
\(\Leftrightarrow\frac{2184\cdot\left(x+33\right)+2002\cdot\left(x+35\right)-1848\cdot\left(x+37\right)-1716\cdot\left(x+39\right)}{24024}=0\)
\(\Leftrightarrow2184x+72072+2002x+70070-1848x-68376-1716x-66924=0\)
\(\Leftrightarrow622x+6842=0\)
\(\Leftrightarrow x=-11\)
Trong không gian với hệ tọa độ Oxyz cho mặt cầu ( S ) : x - 5 2 + y - 1 2 + z + 2 2 = 16 Tính bán kính của (S)
A. 4
B. 6
C. 7
D. 5
bài 1, tìm x ;
a, -16 + 23 + x = -16
b, 2x-35=15
c, 3x+17==12
d, |x-1|=0
e, -13.|x|=-26
bài 2; tính hợp lí ;
a, 35.18-5.7.28
b, 45-5.[12+9]
c, 24. [16-5]-16.[24-5]
d, 29.[19-13]-19.[29-13]
e, 31. [-18]+31. [-81]-31
g, [-12].47+[-12].52+[-12]
f, 13. [23+22]-3.[17+28]
h, -48 + 48. [-78]+48.[-21]
Bài 1. tìm x :
a, -16 + 23 + x = -16
23 + x = -16-(-16)
23 + x = 0
x = 0 - 23
Vậy: x = -23
b, 2x - 35 = 15
2x = 15 + 35
2x = 50
x = 50 : 2
Vậy: x = 25
c, 3x + 17 = 12
3x = 12 - 17
3x = -5
Vậy: x = -5/3
d, | x - 1 | = 0
x - 1 = 0
x = 0 + 1
Vậy: x = 1
e, -13 . | x | = -26
-13 . x = -26
x = -26 : ( -13 )
Vậy: x = 2
Mik làm bài 1 còn bài 2 bn tự làm nha
Hok tốt!!!
Cho S 1 : x - 1 2 + y 2 + z - 2 2 = 1 ; S 2 : x + 1 2 + y + 1 2 + z 2 = 16 . Xác định vị trí tương đối giữa S 1 , S 2 .
Tìm số nguyên x, biết:
a) (x-3) + 11 = -25
b) 5 - (x-1) =12 -16
c) (x-14) + (-22) -6 -12
d) (-15) - (15-x) = -6 + (-8)