a) 121-(118-x)=217 b) [6x-39):7].4=12 c) 11x-7x+x=325 d) 15-x =7-(-2) e) x-[42+(-28)]=-8 20/08/2021 Bởi Ayla a) 121-(118-x)=217 b) [6x-39):7].4=12 c) 11x-7x+x=325 d) 15-x =7-(-2) e) x-[42+(-28)]=-8
$ a)121 – \left( {118 – x} \right) = 217\\ \Rightarrow 121 – 118 + x = 217\\ \Rightarrow 3 + x = 217\\ \Rightarrow x = 214\\ b)\left[ {\left( {6x – 39} \right):7} \right].4 = 12\\ \Rightarrow \left[ {\left( {6x – 39} \right):7} \right] = 3\\ \Rightarrow \left( {6x – 39} \right) = 21\\ \Rightarrow 6x = 60\\ \Rightarrow x = 10\\ c)11x – 7x + x = 325\\ \Rightarrow 5x = 325\\ \Rightarrow x = 65\\ d)15 – x = 7 – \left( { – 2} \right)\\ \Rightarrow 15 – x = 9\\ \Rightarrow – x = – 6\\ \Rightarrow x = 6\\ e)x – \left[ {42 + \left( { – 28} \right)} \right] = – 8\\ \Rightarrow x – \left( {42 – 28} \right) = – 8\\ \Rightarrow x – 14 = – 8\\ \Rightarrow x = 6 $ Bình luận
Giải: \(\begin{array}{l}a)\,121 – \left( {118 – x} \right) = 217\\ \Leftrightarrow \,121 – 118 + x\,\,\,\,\, = 217\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,3\,\,\,\,\,\,\,\,\,\, + x\,\,\,\,\,\, = 217\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\, = 217 – 3\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\, = 214\\b)\,\left[ {\left( {6x – 39} \right):7} \right].4 = 12\\ \Leftrightarrow \,\,\left( {6x – 39} \right):7 = 3\\ \Leftrightarrow \,\,\,\,\,\,6x – 39\,\,\,\,\,\,\, = 21\\ \Leftrightarrow \,\,\,\,\,\,6x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 60\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 10\\c)\,11x – 7x + x = 325\\ \Leftrightarrow \,\,\,\,\,\,5x = 325\\ \Leftrightarrow \,\,\,\,\,\,\,\,x = 325:5\\ \Leftrightarrow \,\,\,\,\,\,\,\,x\, = 65\\d)\,15 – x = 7 – \left( { – 2} \right)\\ \Leftrightarrow \,15 – x\, = 9\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,x = \,15 – 9\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,x = 6\\e)\,x – \left[ {42 + \left( { – 28} \right)} \right] = – 8\\ \Leftrightarrow x – \,\,14\,\,\,\,\,\, = – 8\\ \Leftrightarrow x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 14 – 8\\ \Leftrightarrow x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 6\end{array}\) Bình luận
$ a)121 – \left( {118 – x} \right) = 217\\ \Rightarrow 121 – 118 + x = 217\\ \Rightarrow 3 + x = 217\\ \Rightarrow x = 214\\ b)\left[ {\left( {6x – 39} \right):7} \right].4 = 12\\ \Rightarrow \left[ {\left( {6x – 39} \right):7} \right] = 3\\ \Rightarrow \left( {6x – 39} \right) = 21\\ \Rightarrow 6x = 60\\ \Rightarrow x = 10\\ c)11x – 7x + x = 325\\ \Rightarrow 5x = 325\\ \Rightarrow x = 65\\ d)15 – x = 7 – \left( { – 2} \right)\\ \Rightarrow 15 – x = 9\\ \Rightarrow – x = – 6\\ \Rightarrow x = 6\\ e)x – \left[ {42 + \left( { – 28} \right)} \right] = – 8\\ \Rightarrow x – \left( {42 – 28} \right) = – 8\\ \Rightarrow x – 14 = – 8\\ \Rightarrow x = 6 $
Giải:
\(\begin{array}{l}a)\,121 – \left( {118 – x} \right) = 217\\ \Leftrightarrow \,121 – 118 + x\,\,\,\,\, = 217\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,3\,\,\,\,\,\,\,\,\,\, + x\,\,\,\,\,\, = 217\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\, = 217 – 3\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\, = 214\\b)\,\left[ {\left( {6x – 39} \right):7} \right].4 = 12\\ \Leftrightarrow \,\,\left( {6x – 39} \right):7 = 3\\ \Leftrightarrow \,\,\,\,\,\,6x – 39\,\,\,\,\,\,\, = 21\\ \Leftrightarrow \,\,\,\,\,\,6x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 60\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 10\\c)\,11x – 7x + x = 325\\ \Leftrightarrow \,\,\,\,\,\,5x = 325\\ \Leftrightarrow \,\,\,\,\,\,\,\,x = 325:5\\ \Leftrightarrow \,\,\,\,\,\,\,\,x\, = 65\\d)\,15 – x = 7 – \left( { – 2} \right)\\ \Leftrightarrow \,15 – x\, = 9\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,x = \,15 – 9\\ \Leftrightarrow \,\,\,\,\,\,\,\,\,\,\,x = 6\\e)\,x – \left[ {42 + \left( { – 28} \right)} \right] = – 8\\ \Leftrightarrow x – \,\,14\,\,\,\,\,\, = – 8\\ \Leftrightarrow x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 14 – 8\\ \Leftrightarrow x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 6\end{array}\)