$20s+30s^{2\ }.$

$20s+30s^{\ }.$

$5t^2$

$6t^2$

$t^2$

$9at^2$

$14at^2$

$5at^2$

$7x^2$

$6x^2$

$9x^2$

$13y^3$

$4y^3$

$5y^3$

$14ab^3$

$18ab^3$

$20ab^3$

$13x^2y+9xy^2+11xy$

$13x^2y+9xy^2+15xy$

$7y^2$

$8y^2$

$6y^2$

$40a^2bc^2+30ab^2c+25abc$

$40a^2bc^2+30ab^2c+20abc$

$4a^2$

$6a^2$