a)15+2x=5^10:5^8
b)48:x+17=33
c)7mũ 2x-6 =49
d) (9x+2)×5+28
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a) Ta có: \(3x-5+7x=17-2x+8\)
\(\Leftrightarrow10x-5=25-2x\)
\(\Leftrightarrow10x-5-25+2x=0\)
\(\Leftrightarrow12x-30=0\)
\(\Leftrightarrow12x=30\)
\(\Leftrightarrow x=\frac{30}{12}=\frac{5}{2}\)
Vậy: \(x=\frac{5}{2}\)
b) Ta có: \(13-5x+14=3x-17-9x\)
\(\Leftrightarrow27-5x=-17-6x\)
\(\Leftrightarrow27-5x+17+6x=0\)
\(\Leftrightarrow44+x=0\)
\(\Leftrightarrow x=-44\)
Vậy: x=-44
c) Ta có: \(x-12+4x=25+2x-49\)
\(\Leftrightarrow x-12+4x-25-2x+49=0\)
\(\Leftrightarrow3x+12=0\)
\(\Leftrightarrow x=-4\)
Vậy: x=-4
d) Ta có: \(7x+10+5=3\left(2x-3\right)-9x\)
\(\Leftrightarrow7x+15=6x-9-9x\)
\(\Leftrightarrow7x+15-6x+9+9x=0\)
\(\Leftrightarrow10x+24=0\)
\(\Leftrightarrow10x=-24\)
\(\Leftrightarrow x=-\frac{24}{10}=\frac{-12}{5}\)
Vậy: \(x=-\frac{12}{5}\)
\(a.12+2x=6^3:6^2\\ 12+2x=6\\ 2x=12-6\\ 2x=6\\ x=6:2\\ x=3\)
\(b.48:x+17=33\\ 48:x=33-17\\ 48:x=16\\ x=48:16\\ x=3\)
\(c.\left(9x+2\right).5+28=83\\ \left(9x+2\right).5=83-28\\ \left(9x+2\right).5=55\\ 9x+2=55:5\\ 9x+2=11\\ 9x=11-2\\ 9x=9\\ x=9:9\\ x=1\)
\(d.187-2.\left(x+5\right)=125\\ 2.\left(x+5\right)=187-125\\ 2.\left(x+5\right)=62\\ x+5=62:2\\ x+5=31\\ x=31-5\\ x=26\)
\(-3+x=5-\left(-7\right)\)
\(\Leftrightarrow-3+x=5+7\)
\(\Leftrightarrow-3+x=12\)
\(\Leftrightarrow x=12+3\)
\(\Leftrightarrow x=15\)
Vậy x= 15
\(x-2=2x-7\)
\(\Leftrightarrow x-2+7=2x\)
\(\Leftrightarrow x-\left(2-7\right)=2x\)
\(\Leftrightarrow2-7=x-2x\)
\(\Leftrightarrow-5=-x\)
\(\Leftrightarrow x=5\)
Vậy x= 5
a, \(\dfrac{10}{17}\) + \(\dfrac{5}{-13}\) - \(\dfrac{11}{25}\) + \(\dfrac{7}{17}\) - \(\dfrac{8}{13}\)
= ( \(\dfrac{10}{17}\) + \(\dfrac{7}{17}\)) - ( \(\dfrac{5}{13}\) + \(\dfrac{8}{13}\)) - \(\dfrac{11}{25}\)
= \(\dfrac{17}{17}\) - \(\dfrac{13}{13}\) - \(\dfrac{11}{25}\)
= 1 - 1 - \(\dfrac{11}{25}\)
= - \(\dfrac{11}{25}\)
b, 0,3 - \(\dfrac{93}{7}\) - 70% - \(\dfrac{4}{7}\)
= 0,3 - 0,7 - ( \(\dfrac{93}{7}+\dfrac{4}{7}\))
= - 0,4 - \(\dfrac{97}{7}\)
= - \(\dfrac{2}{5}\) - \(\dfrac{97}{7}\)
= - \(\dfrac{499}{35}\)
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x2 - 16x - 34 = 10x2 + 3x - 34
=> 10x2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0
hoặc 10x - 19 = 0 => 10x = 19 => x = 19/10
Vậy x = 0 ; x = 19/10
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x 2 - 16x - 34 = 10x 2 + 3x - 34
=> 10x 2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0 hoặc 10x - 19 = 0
=> 10x = 19
=> x = 19/10
Vậy x = 0 ; x = 19/10
a) 15 x 21 - 16 : 4 + 7
= 315 - 4 + 7
= 311 + 7
= 318
b) 123 - 11 x 6 + 150 : 30
= 123 - 66 + 5
= 57 + 5
= 62
Mình chỉ làm đến đó thôi chứ mấy câu còn lại khó hiểu quá!Ở lớp 5 mình chưa học bao giờ.
a)
=315-4+7=318
b)
=123-66+5=62
c)
=2017+5x[300-700:7]
=2017+5x[300-100]
=2017+5x200
=2017+1000
=3017
d)
=1560:[5x79-370+5x21]
=1560:[395-370+105]
=1560:130
=12
e)
=50-[12:2+34]
=50-40
=10
g)
=10-[16x5+88]:28
=10-168:28
=10-6
=4
a) \(15+2x=5^{10}:5^8\\ 15+2x=5^2\\ 2x=25-15\\ 2x=10\\ x=10:2\\ x=5\)
b) \(48:x+17=33\\ 48:x=33-17\\ 48:x=16\\ x=48:16\\ x=3\)
c) \(7^{2x-6}=49=7^2\\ 2x-6=2\\ 2x=2+6\\ 2x=8\\ x=8:2\\ x=4\)
d) Bạn xem lại đề nhé
a, \(15+2x=\dfrac{5^{10}}{5^8}=5^2\Leftrightarrow15+2x=25\Leftrightarrow2x=10\Leftrightarrow x=5\)
b, \(\dfrac{48}{x}+17=33\Leftrightarrow\dfrac{48}{x}=33-17=16\Leftrightarrow x=\dfrac{48}{16}=3\)
c, \(7^{2x-6}=49=7^2\Rightarrow2x-6=2\Leftrightarrow x=4\)
d, sửa \(\left(9x+2\right).5=28\Leftrightarrow9x+2=\dfrac{28}{5}\Leftrightarrow9x=\dfrac{18}{5}\Leftrightarrow x=\dfrac{2}{5}\)