Question

giúp e lm bài 7 😁

Answer 1

Bài 7: Tìm số tự nhiên x, biết:

\(a)\left(x+60\right)-160=0\\ \left(x+60\right)=0+160\\ \left(x+60\right)=160\\ x=160-60\\ x=100\\ b)\left(156-9x+61\right)=82\\ \left(217-9x\right)=82\\ 9x=217-82\\ 9x=135\\ x=135:9\\ x=15\) 

\(c)12:\left(3x-7\right)+34=40\\ 12:\left(3x-7\right)=40-34\\ 12:\left(3x-7\right)=6\\ \left(3x-7\right)=12:6\\ \left(3x-7\right)=2\\ 3x=7+2\\ 3x=9\\ x=9:3\\ x=3\\ d)101+\left(105:x-12\right).7=122\\ \left(105:x-12\right).7=122-101\\ \left(105:x-12\right).7=21\\ \left(105:x-12\right)=21:7\\ \left(105:x-12\right)=3\\ 105:x=3+12\\ 105:x=15\\ x=105:15\\ x=7\) 

\(e)12.\left[43-\left(56-x\right)\right]=384\\ \left[43-\left(56-x\right)\right]=384:12\\ \left[43-\left(56-x\right)\right]=32\\ \left(56-x\right)=43-32\\ \left(56-x\right)=11\\ x=56-11\\ x=45\\ f)26-3.\left(x-5\right)=14\\ 26-3x+15=14\\ 41-3x=14\\ 3x=41-14\\ 3x=27\\ x=27:3\\ x=9.\)