Let's assume that number as x
The product of 7 and a number =7x
and then increased by 1
so, it will become
=7x+1
now, it is between 15 and 43
so, we can write as
[tex]15<7x+1<43[/tex]
now, we can solve for x
Since, we have to isolate x
step-1:
Subtract all the sides by 1
[tex]15-1<7x+1-1<43-1[/tex]
[tex]14<7x<42[/tex]
step-2:
Divide all the sides by 7
[tex]\frac{14}{7}<\frac{7x}{7}<\frac{42}{7}[/tex]
[tex]2<x<6 [/tex]
so, solution is
[tex]2<x<6 [/tex].............Answer