Verified answer

y=x√x =x^(3/2)

y'=(3/2)* x^(3/2-1) =(3/2)*√x

y'=(3/2)*√x  é o coeficiente angular da reta tangente

y=1+3x ==> coeficiente angular =3

(3/2)*√x =3

√x =2  ==>x=4  ==>y=4*√4=8 ==>ponto (4,8) de tangencia  

3= (y-8)/(x-4)

3x-12=y-8

3x-y-4= 0  é a equação