1)\(79-5\left(11-x\right)=34\)
\(\Rightarrow79-55+5x=34\)
\(\Rightarrow24+5x=34\)
\(\Rightarrow5x=-10\)
\(\Rightarrow x=-2\)
Vậy \(x=-2\)
2)\(32+2\left(7-x\right)=40\)
\(\Rightarrow32+14-2x=40\)
\(\Rightarrow46-2x=40\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
3)\(\left(166-2x\right).8^9=2.8^{11}\)
\(\Rightarrow\left(83-x\right).2.8^9=2.8^{11}\)
\(\Rightarrow83-x=8^3\)
\(\Rightarrow83-x=512\)
\(\Rightarrow x=-429\)
Vậy \(x=-429\)
4)\(5^2.x-2^3.x=51\)
\(\Rightarrow x\left(5^2-2^3\right)=51\)
\(\Rightarrow x\left(25-8\right)=51\)
\(\Rightarrow17x=51\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
5)\(3^x+4.3^x=5.3^7\)
\(\Rightarrow3^x\left(1+4\right)=5.3^7\)
\(\Rightarrow5.3^x=5.3^7\)
\(\Rightarrow3^x=3^7\)
\(\Rightarrow x=7\)
Vậy \(x=7\)
6)\(7.2^x-2^x=6.32\)
\(\Rightarrow2^x\left(7-1\right)=6.2^5\)
\(\Rightarrow6.2^x=6.2^5\)
\(\Rightarrow2^x=2^5\)
\(\Rightarrow x=5\)
Vậy \(x=5\)
7)\(15^{3-x}=225\)
\(\Rightarrow15^{3-x}=15^2\)
\(\Rightarrow3-x=2\)
\(\Rightarrow x=1\)
Vậy \(x=1\)
8)\(4.5^x-3=97\)
\(\Rightarrow4.5^x=100\)
\(\Rightarrow5^x=25\)
\(\Rightarrow5^x=5^2\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
9)\(171-3.2^x=123\)
\(\Rightarrow3.2^x=48\)
\(\Rightarrow2^x=16\)
\(\Rightarrow2^x=2^4\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
10)\(180-4.x^5=32\)
\(\Rightarrow4.x^5=148\)
\(\Rightarrow x^5=37\)//Đề có lỗi không ???
Mình làm mãi mới xong nên k đúng hộ mình nha
1) \(79-5.\left(11-x\right)=34\) 2) \(32+2.\left(7-x\right)=40\)
\(5.\left(11-x\right)=79-34\) \(2.\left(7-x\right)=40-32\)
\(5.\left(11-x\right)=45\) \(2.\left(7-x\right)=8\)
\(11-x=45:5\) \(7-x=8:2\)
\(11-x=9\) \(7-x=4\)
\(x=11-9\) \(x=7-4\)
\(x=2\) \(x=3\)
3) \(\left(166-2.x\right).8^9=2.8^{11}\) 4) \(5^2.x-2^3.x=51\)
\(\left(166-2.x\right)=2.8^{11}:8^9\) \(25.x-8.x=51\)
\(\left(166-2.x\right)=2.8^2\) \(\left(25-8\right).X=51\)
\(\left(166-2.x\right)=2.64\) \(17.x=51\)
\(166-2.x=128\) \(x=51:17\)
\(2.x=166-128\) \(x=3\)
\(2.x=38\)
\(x=38:2\)
\(x=19\)
5) \(3^x+4.3^x=5.3^7\) 6) \(7.2^x-2^x=6.32\)
\(3^x+4.3^x=5.2187\) \(7.2^x-2^x=192\)
\(\left(1+4\right).3^x=10935\) \(\left(7-1\right).2^x=192\)
\(5.3^x=10935\) \(6.2^x=192\)
\(3^x=10935:5\) \(2^x=192:6\)
\(3^x=2187\) \(2^x=32\)
\(3^x=3^7\) \(2^x=2^5\)
\(=>x=7\) \(=>x=5\)
7)\(15^{3-x}=225\) 8) \(4.5^x-3=97\)
\(15^{3-x}=15^2\) \(4.5^x=97+3\)
\(=>x=3-2\) \(4.5^x=100\)
\(x=1\) \(5^x=100:4\)
\(5^x=25\)
\(5^x=5^2\)
\(=>x=2\)
9) \(171-3.2^x=123\)
\(3.2^x=171-123\)
\(3.2^x=48\)
\(2^x=48:3\) \(\)
\(2^x=16\)
\(2^x=2^4\)
\(=>x=4\)
Câu 10 mình ko làm được vì nó cứ sai sai đề í