Tìm X :
\(a,\left(x+17\right)\times21-3=7\) \(e,3^x=3^{^2}\times9\)
\(b,5^{x-1}-13=612\) \(f,2^{3x+4}=1024\)
\(c,218-5\times\left(x+8\right)=25\div2^2\) \(g,3\left(x+6\right)+72=4^2\times3^2\)
\(d,4\times3^x=36\) \(i,\left(21+x\right)\div9=9^5\times9^4\)
Giúp mk với!!!!!!
\(\left(x+17\right)\times21-3=7\)
\(\left(x+17\right)\times21=7+3\)
\(\left(x+17\right)\times21=10\)
\(x+17=10:21\)
\(x+17=\frac{10}{21}\)
\(x=\frac{10}{21}-17\)
\(x=-\frac{347}{21}\)
\(b,5^{x-1}-13=612\)
\(5^{x-1}=612+13\)
\(5^{x-1}=625\)
\(5^{x-1}=5^4\)
\(x-1=4\)
\(x=4+1\)
\(x=5\)
\(e,3^x=3^2\times9\)
\(3^x=3^2\times3^2\)
\(3^x=3^4\)
\(\Rightarrow x=4\)
\(f,2^{3x+4}=1024\)
\(2^{3x+4}=2^{10}\)
\(\Rightarrow3x+4=10\)
\(\Rightarrow3x=10-4\)
\(\Rightarrow3x=6\)
\(\Rightarrow x=2\)