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

"see explanation"see explanation

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 5n13

rArr3(n+7)>5n-13larrcolor(red)" is the inequality"3(n+7)>5n13 is the inequality

"distribute the brackets on the left side"distribute the brackets on the left side

3n+21>5n-133n+21>5n13

"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