A =
B = +
Tìm x, biết:
a ) | x | − 1 2 = 3 4 ; b ) x − 1 2 = 1 c ) x − 1 2 − 3 4 = 1 4 ; d ) 1 20 − 3 2 − x = 1 40 e ) x + 1 3 2 − 4 9 = 0 f ) x + 1 3 2 + 4 9 = 8 9
a ) x = 5 4 x = − 5 4 b ) x = 3 2 x = − 1 2 c ) x = 3 2 x = − 1 2
d ) x = 59 40 x = 61 40 e ) x = 1 3 x = − 1 f ) x = 1 3 x = − 1
Tìm x biết:
a ) | x | = 1 5 + 3 4 ; b ) | x − 5 | = − − 5 3 + 1 4 ;
c ) x − 1 4 = 3 2 + 1 3 − 7 6 ; d ) x − 4 3 = 1 6 + 5 3 − 1 2 + 7 12 .
a ) x = 19 20 x = 19 20 b ) x = 83 12 x = − 37 12
c ) x = 31 12 x = − 25 12 d ) x = 13 4 x = − 7 12
Tìm x, biết:
a/ x 2 = y 3 và xy = 54
b / x − 1 2 = y − 2 3 = z − 3 4 và 2x + 3y –z = 50
c/ 3x = 2y; 7y = 5z và x – y + z = 32
tính nhanh
92 + 71 + 108 , 32 x 47 + 53 x 47 + 47 x 15
90 x 143 - 43 x 90 , ( 1200 + 60 ) : 12
2 x 18 x 24 + 3 x 50 x 16 + 12 x 32 x 4
34 x 81 + 34 x 19 + 66 x 35 + 47 x 66
48 x 29 + 48 x 71 - ( 12 x 45 + 12 x 55 )
92 + 71 + 108 = (92 + 108) + 71 = 200 + 71 = 271
32 x 47 + 53 x 47 + 47 x 15 = 47(32 + 53 + 15)
= 47.100
= 4700
90 x 143 - 43 x 90 = 90.(143 - 43) = 90.100 = 9000
(1200 + 60) : 12 = 1800 : 12 = 150
2 x 18 x 24 + 3 x 50 x 16 + 12 x 32 x 4 = 18.(2.24) + 50.(3.16) + 32.(12.4) = 18.48 + 50.48 + 32.48 = 48(18 + 50 + 32) = 48.100 = 4800
92+71+108=71+(92+108)=71+200=271
90x143-43x90=90x(143-43)=90x100=9000
32x47+53x47+47x15=47x(32+53+15)=47x100=4700
(1200+60):12=1260:12=105
2x18x24+3x50x16+12x32x4=(2x24)x18+(3x16)x50+(12x4)x32
=48x18+48x50+48x32
=48x(18+50+32)
=48x100=4800
Tìm x, biết
a) x : − 2 1 15 + 3 1 2 = − 3 4 b) − 5 8 − x : 3 5 6 + 7 3 4 = − 2
c) x − 3 4 − 1 4 = 0 d) 3 4 : 2 4 9 − − 3 x + 2 2 3 = 3 4
e) x − 1 3 = 2 − 3 x f) 3 5 7 x − 1 5 7 x − 1 3 = 2 3
g) − 3 4 3 x − 1 = − 27 64 h) 4 5 2 x + 5 = 256 625
i) x − 2 15 3 = 8 125 k) x + 3 5 x + 3 2 = 64 27
m) x − 1 x + 5 = 6 7 n) 4 13 . 6 5 + 4 13 . 2 5 . 2 x + 1 2 = 10 13
Tính nhanh các giá trị biểu thức dưới đây:
a) 576 + 678 + 780 – 475 - 577 - 679
b) (126 + 32) x (18 - 16 - 2)
c) 36 x 17 x 12 x 34 + 6 x 30
a) 576 + 678 + 780 - 475 - 577 - 679
= 780 - 475 + ( 576 - 577) - ( 678 - 679)
= 305 - 1 - 1
= 303
b) (126 + 32)\(\times\)(18 - 16 - 2)
= (126 + 32) \(\times\)0
= 0
c) 36 * 17 * 12 * 34 + 6 * 30
= 36 * 17 * 6 * 2 * 34 + 6 * 30
= 6 * (36 + 17 + 2 + 34 + 30)
= 6 * 119
= 714
\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)
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tìm x \(\in\)Z biết
a) 34+(9-21)=3417-(x+341)
b)(15-x)+(x-12)=7-(-8+x
c) x-{55-[49+(-28-x)]}=13-{47+[25-(32-x)]}
d) -7+lx+4l=-3
e) lx-10l-(-12)=4
34 + (9-21)=3417-(x+341)
22 = 3417-(x+341)
3417-(x+341)=22
x+341=3417-22
x+341=3395
x=3395-341 ; x =3054
Xin lỗi Quảng Bùi Quỳnh Trang, tớ lỡ bấm vào sai rồi
I'm sorry
lx-10l-(-12)=4
=lx-10l+12=4
=x-10 =4-12
=lx-10l =-8
cha ! tiep theo minh tac ti rui .Phan truoc khong biet dung khong
Câu 16: Tìm số tự nhiên x biết
a)2x + 5 = 34 . 32.
𝑏) 120 – (𝑥 + 55) = 60.
c)x ⋮ 12 và x < 60.
a) \(\Leftrightarrow2x+5=3^6\\ \Leftrightarrow2x+5=729\\ \Leftrightarrow x=362\)
b) \(\Leftrightarrow x+55=60\\ \Leftrightarrow x=5\)
c) \(x=\left\{12;24;36;48\right\}\)
c) x ⋮ 12 và x < 60
x ∈ B(12) = { 0 ; 12 ; 24 ; 36 ; 48 ; 60 ;...}
mà x ⋮ 12 và x < 60
nên x ∈ B(12)= { 0 ; 12 ; 24 ; 36 ; 48 }
Tìm x Biết:
\(\frac{x+32}{11}+\frac{x+33}{12}=\frac{x+34}{13}+\frac{x+35}{14}\)
\(\frac{x+32}{11}+\frac{x+33}{12}=\frac{x+34}{13}+\frac{x+35}{14}\)
\(\Leftrightarrow\left(\frac{x+32}{11}-1\right)+\left(\frac{x+33}{12}-1\right)=\left(\frac{x+34}{13}-1\right)+\left(\frac{x+35}{14}-1\right)\)
\(\Leftrightarrow\frac{x-21}{11}+\frac{x-21}{12}=\frac{x-21}{13}+\frac{x-21}{14}\)
\(\Leftrightarrow\left(x-21\right)\left(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
Vì \(\left(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)\ne0\)
\(\Rightarrow x-21=0\Rightarrow x=21\)
\(\frac{x+32}{11}+\frac{x+33}{12}=\frac{x+34}{13}+\frac{x+35}{14}\)
\(\Leftrightarrow\left(\frac{x+32}{11}-1\right)+\left(\frac{x+33}{12}-1\right)=\left(\frac{x+34}{13}-1\right)+\left(\frac{x+35}{14}-1\right)\)( trừ cả hai vế cho 2 )
\(\Leftrightarrow\frac{x-21}{11}+\frac{x-21}{12}=\frac{x-21}{13}+\frac{x-21}{14}\)
\(\Leftrightarrow\frac{x-21}{11}+\frac{x-21}{12}-\frac{x-21}{13}-\frac{x-21}{14}=0\)
\(\Leftrightarrow\left(x-21\right)\left(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
Mà \(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\ne0\)
\(\Rightarrow x-21=0\)
\(\Leftrightarrow x=21\)
Vậy \(x=21\)