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Answer: the answer is 7

Step-by-step explanation: add 9 to both sides, eliminating -9 so now you have 7x=49 divide both by 7 and you get x= 7 check it by inputing 7 for x, 7(7)-9=40

7(7)=49 next 49-9= 40

it checks out, so x= 7

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