Aiuto con matematica equazione della retta passante per 3 punti​

Plzzz answer both questions and i will give you 100 points

Will mark 50 show all what is the solution to the system of equations? use the substitution method and show your work. -5x+y= -3 -15 x+3y=7 explain what your answer in part (a) tells you about the association of the lines in this system.

Aley is at the store buying some supplies for an art project. she decides to buy some colored pencils for $3.95 and a drawing tablet. the total cost of the supplies before sales tax is $6.94. what is the cost of the drawing tablet? $10.89 $2.99 $1.76 $3.01