\(a)24\times(x-16)=12^2\\\Rightarrow 24\times(x-16)=144\\\Rightarrow x-16=144:24\\\Rightarrow x-16=6\\\Rightarrow x=6+16\\\Rightarrow x=22\\---\\b)(x^2-10):5=5\\\Rightarrow x^2-10=5\times5\\\Rightarrow x^2-10=25\\\Rightarrow x^2=25+10\\\Rightarrow x^2=35\\\Rightarrow x=\pm\sqrt{35}\\---\)

\(c)(5x+335):2=400\\\Rightarrow 5x+335=400\times2\\\Rightarrow 5x+335=800\\\Rightarrow 5x=800-335\\\Rightarrow 5x=465\\\Rightarrow x=465:5\\\Rightarrow x=93\\---\\d)63:(5x+4)=2^3-1\\\Rightarrow 63:(5x+4)=8-1\\\Rightarrow 63:(5x+4)=7\\\Rightarrow 5x+4=63:7\\\Rightarrow 5x+4=9\\\Rightarrow 5x=9-4\\\Rightarrow 5x=5\\\Rightarrow x=5:5\)

\(\Rightarrow x=1\)

\(Toru\)

a: \(280-\left(x-140\right):35=270\)

=>(x-140):35=280-270=10

=>x-140=350

=>x=350+140

=>x=490

b: \(\left(190-2x\right):35-32=16\)

=>\(\left(190-2x\right):35=32+16=48\)

=>\(190-2x=35\cdot48=1680\)

=>2x=190-1680=-1490

=>x=-745

c: \(720:\left\lbrack41-\left(2x-5\right)\right\rbrack=2^3\cdot5\)

=>\(720:\left\lbrack41-\left(2x-5\right)\right\rbrack=8\cdot5=40\)

=>41-(2x-5)=720:40=18

=>2x-5=41-18=23

=>2x=28

=>x=14

d: \(\left(x:23+45\right)\cdot37-22=2^4\cdot105\)

=>\(\left(\frac{x}{23}+45\right)\cdot37=16\cdot105+22=1702\)

=>\(\frac{x}{23}+45=46\)

=>\(\frac{x}{23}=1\)

=>x=23

e: \(\left(3x-4\right)\left(x-1\right)^3=0\)

=>\(\left[\begin{array}{l}3x-4=0\\ x-1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac43\\ x=1\end{array}\right.\)

f: \(2^{2x-1}:4=8^3\)

=>\(2^{2x-1-2}=2^9\)

=>2x-3=9

=>2x=12

=>x=6

g: \(x^{17}=x\)

=>\(x^{17}-x=0\)

=>\(x\left(x^{16}-1\right)=0\)

=>\(\left[\begin{array}{l}x=0\\ x^{16}-1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x^{16}=1\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=1\\ x=-1\end{array}\right.\)

h: \(\left(x-5\right)^4=\left(x-5\right)^6\)

=>\(\left(x-5\right)^6-\left(x-5\right)^4=0\)

=>\(\left(x-5\right)^4\cdot\left\lbrack\left(x-5\right)^2-1\right\rbrack=0\)

=>\(\left(x-5\right)^4\cdot\left(x-4\right)\left(x-6\right)=0\)

=>x∈{4;5;6}

i: \(\left(x+2\right)^5=2^{10}\)

=>\(\left(x+2\right)^5=\left(2^2\right)^5=4^5\)

=>x+2=4

=>x=2

k: 1+2+3+...+x=78

=>\(\frac{x\left(x+1\right)}{2}=78\)

=>x(x+1)=156

=>\(x^2+x-156=0\)

=>(x+13)(x-12)=0

=>x=-13(loại) hoặc x=12(nhận)

l: \(\left(3x-2^4\right)\cdot7^3=2\cdot7^4\)

=>\(3x-16=2\cdot\frac{7^4}{7^3}=2\cdot7=14\)

=>3x=16+14=30

=>\(x=\frac{30}{3}=10\)

n: \(5^{x}:5^2=125\)

=>\(5^{x-2}=5^3\)

=>x-2=3

=>x=5

m: \(\left(x+1\right)^2=\left(x+1\right)^0\)

=>\(\left(x+1\right)^2=1\)

=>\(\left[\begin{array}{l}x+1=1\\ x+1=-1\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=-2\end{array}\right.\)

o: Số số hạng của dãy số 2;4;..;52 là:

(52-2):2+1=50:2+1=25+1=26(số)

Tổng của dãy số 2;4;...;52 là:

\(\left(52+2\right)\cdot\frac{26}{2}=54\cdot13=702\)

(2+x)+(4+x)+...+(52+x)=780

=>26x+702=780

=>26x=78

=>x=3

p: \(70=2\cdot5\cdot7;80=2^4\cdot5\)

=>ƯCLN(70;80)=\(2\cdot5=10\)

70⋮x; 80⋮x

=>x∈ƯC(70;80)

=>x∈Ư(10)

mà x>8

nên x=10

q: \(12=2^2\cdot3;25=5^2;30=2\cdot3\cdot5\)

=>BCNN(12;25;30)=\(2^2\cdot3\cdot5^2=300\)

x⋮12; x⋮25; x⋮30

=>x∈BC(12;25;30)

=>x∈B(300)

mà 0<x<500

nên x=300

a) x = 15

b) x = 11

c) x = 68

d) x = 310

(x4)3=x6x19

a) x = 15.              b)      x = 11.        c) x = 68.              d) x = 310

Tìm xx biết:    \left(x^{4}\right)^{3}=\dfrac{x^{19}}{x^{6}}(x4)3=x6x19​

Trả lời: x=x= 

a, x=15
b, x=11
c, x=7
d, x=36

Bài 6:

a)(x-15).15=0

⇔x-15=0

⇔x=15

b)32(x-10)=32

⇔x-10=1

⇔x=11

c)(x-5)(x-7)=0

⇔x-5=0 hay x-7=0

⇔x=5 hay x=7

d)(x-35)35=35

⇔x-35=1

⇔x=36

a: x⋮5

=>x∈{0;5;10;15;20;25;30;35;40;45;...}
mà 20<x<40

nên x∈{25;30;35}

b: 30⋮x

=>x∈{1;2;3;5;6;10;15;30}

mà x<10

nên x∈{1;2;3;5;6}

c: Ta có: \(10=2\cdot5;12=2^2\cdot3;15=3\cdot5\)

=>BCNN(10;12;15)\(=2^2\cdot3\cdot5=60\)

x⋮10; x⋮12; x⋮15

=>x∈BC(10;12;15)

=>x∈B(60)

mà 0<x<150

nên x∈{60;120}

d: \(24=2^3\cdot3;30=2\cdot3\cdot5;36=2^2\cdot3^2\)

=>ƯCLN(24;30;36)\(=2\cdot3=6\)

24⋮x; 30⋮x; 36⋮x

=>x∈ƯC(24;30;36)

=>x∈Ư(6)

mà x lớn nhất

nên x=6

e: \(5=5;6=2\cdot3;7=7\)

=>BCNN(5;6;7)\(=5\cdot2\cdot3\cdot7=10\cdot21=210\)

x∈BC(5;6;7)

mà x là số nhỏ nhất khác 0

nên x=BCNN(5;6;7)=210

f: \(20=2^2\cdot5;25=5^2;30=2\cdot3\cdot5\)

=>ƯCLN(20;25;30)=5

x∈ƯC(20;25;30)

=>x∈Ư(5)

mà x>=5

nên x=5

mik đang cần gấp 

Đáp số:

a) x=15

b) x=11

c) x=68

d) x=310

(x-3.5).12=0

X-15        =0+15

     x         =15

Bài 6:

a)(x-15).15=0

⇔x-15=0

⇔x=15

b)32(x-10)=32

⇔x-10=1

⇔x=11

c)(x-5)(x-7)=0

⇔x-5=0 hay x-7=0

⇔x=5 hay x=7

d)(x-35)35=35

⇔x-35=1

⇔x=36

a: \(\left(x-15\right)\cdot15=0\)

=>x-15=0

=>x=0+15

=>x=15

b: 32(x-10)=32

=>x-10=32/32=1

=>x=1+10=11

c: (x-5)(x-7)=0

=>\(\left[\begin{array}{l}x-5=0\\ x-7=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=5\\ x=7\end{array}\right.\)

d: \(\left(x-35\right)\cdot35=35\)

=>\(x-35=\frac{35}{35}=1\)

=>x=1+35

=>x=36