T + 1 -3t < - 20 ------(a)

To solve this inequality first we convert it into simple form.

t-3t+1 < -20

-2t+1 < -20

-2t < -20-1

-2t<-21

-t<-21/2

we multiply minus sign on the both sides.

t> 21/2

The sign of inequality changes according to the property of inequality.

the associated equation is;

t= 21/2

It is linear equation so it has only one root.

equation (a) satisfies only when t>21/2

so the solution of inequality is ]21/2 +infinity[

To solve this inequality first we convert it into simple form.

t-3t+1 < -20

-2t+1 < -20

-2t < -20-1

-2t<-21

-t<-21/2

we multiply minus sign on the both sides.

t> 21/2

The sign of inequality changes according to the property of inequality.

the associated equation is;

t= 21/2

It is linear equation so it has only one root.

equation (a) satisfies only when t>21/2

so the solution of inequality is ]21/2 +infinity[