Bài 2: Tìm số tự nhiên x, biết:
a) \(43-\left(24-x\right)=20\)
\(24-x=43-20\)
\(24-x=23\)
\(x=24-23\)
\(x=1\)
b) \(2\left(x-5\right)-17=25\)
\(2\left(x-5\right)=25+17\)
\(2\left(x-5\right)=8\)
\(x-5=8:2\)
\(x-5=4\)
\(x=4+5\)
\(x=9\)
c) \(3\left(x+7\right)-15=27\)
\(3\left(x+7\right)=27+15\)
\(3\left(x+7\right)=42\)
\(x+7=42:3\)
\(x+7=14\)
\(x=14-7\)
\(x=7\)
d) \(15+4\left(x-2\right)=95\)
\(19\left(x-2\right)=95\)
\(x-2=95:19\)
\(x-2=5\)
\(x=5+2\)
\(x=7\)
e) \(20-\left(x+14\right)=5\)
\(x+14=20-5\)
\(x+14=15\)
\(x=15-14\)
\(x=1\)
f) \(24-3\left(5-x\right)=27\)
\(3\left(5-x\right)=24-27\)
\(3\left(5-x\right)=-3\)
\(5-x=-3:3\)
\(5-x=-1\)
\(x=5-\left(-1\right)\)
\(x=6\)
Chúc bạn học tốt
