Please solve this..you have to find x

What is solution for the following system of equations, 2x+8y=4 and x=-3y+5 1) x=14 y=-3 2) x=2 y=-3 3) x=-3 y=-3 4)x=12 y=5

The price of a visit to the dentist is \$50$50. if the dentist fills any cavities, an additional charge of \$100$100 per cavity gets added to the bill. if the dentist finds nn cavities, what will the cost of the visit be?

Find the simplified product: 2sqrt 5x^3(-3sqrt10x^2) a: -30sqrt2x^5 b: -30x^2sqrt2x c: -12x^2sqrt5x d: -6sqrt50x^5