Circle the systems below that represent linear systems of differential equations.

$y_1^{\text{'}}=y_{2}t,x^{\text{'}}=3-xy,x^{\text{'}}=t^{2}z{t}^{2}x$

$y_2^{\text{'}}=y_{3}t,y^{\text{'}}=4-yz,y^{\text{'}}=t^{2}y{t}^{2}z$

$y_3^{\text{'}}=y_1{t}^2,z^{\text{'}}=5-xz,z^{\text{'}}=t^{2}x{t}^{2}y$

Rewrite the following differential equation as a system of first$-$order linear

ODEs:

$y^{\text{'}\text{'}\text{'}}2y^{\text{'}\text{'}}-3t{y}^{\text{'}}4=t^7$