Tìm x
$( 19x + 2 . 5^{2}$ ) ; 14 = $( 13 - 8 )^{2}$ - $4^{2}$
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a.12x+19x-123=280
12x+19x =280+123
12x+19x =403
31x =403
x=403:31
x=13
b. 5-(17-3)=x-(2-15)
5-14 =x-(-13)
-9 =x+13
=> x=(-9)-13=-22
Tìm x:
a. 12x + 19x - 123 = 280
(12 + 19).x - 123 = 280
31.x - 123 = 280
31.x = 280 + 123
31.x = 403
x = 403 : 31
x = 13
Thôi để t làm nốt cho
c )
Ta có :
\(x+5⋮2x-1\)
\(\Leftrightarrow2\left(x+5\right)⋮2x-1\)
\(\Leftrightarrow2x+10⋮2x-1\)
\(\Leftrightarrow2x-1+11⋮2x-1\)
\(\Leftrightarrow11⋮2x-1\)
\(\Leftrightarrow2x-1\inƯ\left(11\right)\)
\(\Leftrightarrow2x-1\in\left\{1;-1;11;-11\right\}\)
\(\Leftrightarrow2x\in\left\{2;0;12;-10\right\}\)
\(\Leftrightarrow x\in\left\{1;0;6;-5\right\}\)
a ) \(\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)
\(\Rightarrow\left(19x+2.25\right):14=5^2-16\)
\(\Rightarrow\left(19x+50\right):14=25-16\)
\(\Rightarrow\left(19x+50\right):14=9\)
\(\Rightarrow19x+50=9.14\)
\(\Rightarrow19x+50=126\)
\(\Rightarrow19x=126-50\)
\(\Rightarrow19x=76\)
\(\Rightarrow x=76:19\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
b ) Số lượng số dãy số trên là :
( x - 1 ) : 1 + 1 = x ( số )
Tổng dãy số trên là :
( x + 1 ) . x : 2 = 378
=> ( x + 1 ) . x = 378 . 2
=> ( x + 1 ) . x = 756
=> x = 27 hoặc x = -28
Vậy x = 27 hoặc x = -28
c ) Tự làm nhé
a) \(\left(19x+2\cdot5^2\right)\div14=\left(13-8\right)^2-4^2\)
\(\left(19x+2\cdot25\right)\div14=5^2-16\)
\(\left(19x+50\right)\div14=25-16=9\)
\(19x+50=9\cdot14=126\)
\(19x=126-50=76\)
\(x=76\div19=4\)
b) \(2\cdot3^x=10\cdot3^{12}+8\cdot\left(3^3\right)^4\)
\(2\cdot3^x=\left(10+8\right)\cdot3^{12}\)
\(2\cdot3^x=18\cdot3^{12}\)
\(\Rightarrow2\cdot3^x=2\cdot3^2\cdot3^{12}\Rightarrow2\cdot3^x=2\cdot3^{15}\Rightarrow x=15\)
a, \left(19.x+2.5^2\right)\div14=\left(13-8\right)^2-4^2(19.x+2.52)÷14=(13−8)2−42
\left(19.x+2.25\right)\div14=5^2-4^2(19.x+2.25)÷14=52−42
\left(19.x+2.25\right)\div14=25-16(19.x+2.25)÷14=25−16
\left(19.x+50\right)\div14=9(19.x+50)÷14=9
\left(19.x+50\right)=9.14(19.x+50)=9.14
19.x+50=12619.x+50=126
19.x=126-5019.x=126−50
19.x=7619.x=76
\Rightarrow x=76\div19⇒x=76÷19
\Rightarrow x=4⇒x=4
Vậy x = 4
b, 2.3^x=10.3^{12}+8.27^42.3x=10.312+8.274
2.3^x=10.3^{12}+8.\left(3^3\right)^42.3x=10.312+8.(33)4
2.3^x=10.3^{12}+8.3^{12}2.3x=10.312+8.312
2.3^x=\left(10+8\right).3^{12}2.3x=(10+8).312
2.3^x=18.3^{12}2.3x=18.312
2.3^x=2.3^3.3^{12}2.3x=2.33.312
2.3^x=2.3^{15}2.3x=2.315
\Rightarrow x=15⇒x=15
Vậy x = 15
câu b sai rồi,thế này mới đúng nè:
b,(19x+2.55):4=(13-8)2-42
(19x+2.52):14=52-42
(19x+2.52):14=8
19x+2.52+126
19x+50=126
19x=76
x=4
\(a.\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)
\(\Leftrightarrow\left(19x+50\right):14=25-16\)
\(\Leftrightarrow\left(19x+50\right):14=9\)
\(\Leftrightarrow19x+50=126\)
\(\Leftrightarrow19x=76\)
\(\Leftrightarrow x=4\)
\(b.\left(x-10\right):2=5-2\left(x+1\right)\)
\(\Leftrightarrow\left(x-10\right):2=5-2x-2\)
\(\Leftrightarrow\frac{1}{2}x-5=3-2x\)
\(\Leftrightarrow\frac{1}{2}x+2x=3+5\)
\(\Leftrightarrow\frac{5}{2}x=8\)
\(\Leftrightarrow x=3,2\)
`( 19x + 2*5^2 ) : 14 = ( 13-8)^2 - 4^2`
`=> ( 19x + 50 ) : 14 = 5^2 - 4^2`
`=> ( 19x + 50 ) : 14 = 9`
`=> 19x + 50 = 9*14`
`=> 19x + 50 = 126`
`=> x = ( 126 - 50 )/19`
`=> x = 4`
Vậy `x=4`
(19x + 2.5\(^2\) ) : 14 = 5\(^2\)- 4\(^2\)
(19x + 2.5\(^2\) ) : 14 = 9
19x + 2.5\(^2\) = 9.14
19x + 50 = 126
19x = 126-50=76;19
x = 4