According to the LP model and its optimal table given below, please answer the following questions:

$-$ If the right hand side of the original problem is changed into $[751550]$T what will be the new optimal solution?

If the objective function coefficient of x$1$ in the original problem is changed into $15$ what will be the new optimal solution?

If a new variable whose objective function coefficient is $60$ and technological constraints are $[231]$T is added to the problem; what is the new optimal solution?maxZ$=35x_1+50x_2$

$st.$

$4x_1+6x_{2}120$

$x_1+x_{2}20$

$2x_1+3x_{2}40$

$x_1,x_{2}0$