How do you write an inequality and solve given "three times the sum of a number and seven is greater than five times the number less thirteen"?
1 Answer
Sep 4, 2017
Explanation:
"let n be the number"let n be the number
"then the sum of this number and 7 is "n+7then the sum of this number and 7 is n+7
"and 3 times this sum is "3(n+7)and 3 times this sum is 3(n+7)
"5 times the number less thirteen is "5n-135 times the number less thirteen is 5n−13
rArr3(n+7)>5n-13larrcolor(red)" is the inequality"⇒3(n+7)>5n−13← is the inequality
"distribute the brackets on the left side"distribute the brackets on the left side
3n+21>5n-133n+21>5n−13
"subtract 3n from both sides"subtract 3n from both sides
cancel(3n)cancel(-3n)+21>5n-3n-13
rArr21>2n-13
"add 13 to both sides"
21+13>2ncancel(-13)cancel(+13)
rArr34>2n
"divide both sides by 2"
17>nrArrn<17