2 ^5.3^12.7^8 phần 2^7.3^10.7^9
\(5.3^x=5.3^4\)
\(5.3^x=7.3^5-2:3^5\)
5.3x = 5.34
=> x = 4
5.34 = 7.35 - 2.35
= 35 . (7 - 2)
= 5. 35
=> 3x = 35
=> x = 5
a) Ta có: \(5\cdot3^x=5\cdot3^4\)
\(\Leftrightarrow3^x=3^4\)
hay x=4
7.3+9.x+(-9.8)-5.3=1
tim x biet
X+35=-22-X
(6X-4^2) .7^8=2.7^9
5.3^x-1-7.3^12=8.3^12
3.(x-15)^3=-24
lx+18l=10
A. 3^n-1+2.3^n+1=8^2
b:1/5.3^n=7.3^2.9^2-2.3^n
C:7^n+2+2.7^n-1=345
TYính giá trị các biểu thức sau
a,A=5^4+2^2.5^2-125 phần 2^3.3
B,b=9^9.32^9 phần 64^7.27^6
c,C=15.27^7.3^8-9^15 phần (2.9^8)^2
Tìm số nguyên x , nếu biết
1. 7.4^x=7.4^3
2.3/2.5^x =3/2.5^12
3 . 2^x=2.2^8
4. 5.3^x=7.3^5-2.3^5
1) \(7.4^x=7.4^3\Leftrightarrow4^x=4^3;x=3\)
2) \(\frac{3}{2.5^x}=\frac{3}{2.5^{12}}\Leftrightarrow5^x=5^{12};x=12\)
\(2^x=2.2^8=2^9;x=9\)
4) \(5.3^x=7.3^5-2.3^5\Leftrightarrow5.3^x=3^5.\left(7-2\right)\)
\(\Leftrightarrow3^5.x=3^5.5;x=5\)
Rút gọn rồi quy đồng mẫu các phân số sau :
a)\(\frac{5.6+5.7}{5.8+20}\)và\(\frac{8.9-4.15}{12.7-180}\)
b)\(\frac{-5^2-5.3^2}{5^3+5^2.3^2}\)và \(\frac{4^6.9^5+69.120}{8^4.3^{12}-6^{11}}\)
\(a,\frac{5\cdot6+5\cdot7}{5\cdot8+20}=\frac{\left(5\cdot6+5\cdot7\right)\div2}{\left(5.8+20\right)\div2}=\frac{13}{12}\)
\(\frac{8.9-4.15}{12.7-180}=\frac{12.6-12.5}{12.7-12.15}=\frac{1}{-8}=\frac{-1}{8}\)
\(Ta\)\(co\)\(\frac{13}{12}=\frac{13.2}{12.2}=\frac{26}{24}\)
\(\frac{-1}{8}=\frac{3\left(-1\right)}{3.8}=\frac{-3}{24}\)
Phần b bạn tính ra rồi làm tương tự phần a nha chúc bạn học giỏi!!!
Bài 2 )
\(5.3^x=5.3^4\)
\(9.5^3=6.5^0+3.5^0\)
\(7.3^x=5.3^7+2.3^7\)
giải đầy đủ ra nhé
nhanh mk cần gấp
5.3x=5.34
<=> 3x=34( chia cả hai vế cho 5)
<=> x=4
7.3x=5.37+2.37
<=> 7.3x=37.(5+2)
<=> 7.3x=37.7
<=> 3x=37(chia cả hai vế cho 7)
<=> x=7
Tìm x biết :
4/x=8/6
3/x-5=-4/x+2
X/-2=-8/x
Rút gọn các phân số
2^4.5^2.11^2.7/2^3.5^3.7^2.11
2^10.3^10-2^10.3^9/2^9.3^10
5^11.7^12+5^12.7^11/5^12.7^12+9.5^11.7^11
1. Tìm x, biết:
a) \(\frac{4}{x}=\frac{8}{6}\). Ta có: \(\frac{8}{6}=\frac{8:2}{6:2}=\frac{4}{3}\Rightarrow x=3\)
b) \(\frac{3}{x-5}=\frac{4}{x+2}\). Ta có: \(5-2=3\)
\(\Rightarrow x=\left(3.5\right)+\left(4.2\right)+3=15+8+3=26\)
c) \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x=\left(-8\right):\left(-2\right)=4\)
2. Rút gọn
a) \(\frac{2^4.5^2.11^2.7}{2^3.5^3.7^2.11}\Leftrightarrow\frac{2^3.2^1.5^2.11.11.7}{2^3.5^2.5^1.7.7.11}\Leftrightarrow\frac{2^1.11}{5^1.7}=\frac{22}{35}\)
b) Tương tự
c) Tương tự
\(\frac{4}{x}=\frac{8}{6}\Rightarrow x=\frac{4.6}{8}=3\)
\(\frac{3}{x-5}=\frac{-4}{x+2}\Rightarrow3\left(x+2\right)=-4\left(x-5\right)\)
\(\Rightarrow3x+6=-4x+20\)
\(\Rightarrow3x+4x=20-6\)
\(\Rightarrow7x=14\)
\(\Rightarrow x=2\)
\(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x^2=\left(-8\right)\left(-2\right)=16\Rightarrow x=\pm4\)
\(\frac{4}{x}=\frac{8}{6}\)
\(\Rightarrow4\cdot6=x\cdot8\)
\(\Rightarrow x=\frac{4\cdot6}{8}\)
\(\Rightarrow x=3\)