Use the 3x-9y=-18 equation and add 9y to both sides to have 3x on its own on the left side. Then, divide by 3 on both sides. Then you'll have x=-6+3y. Plus this back into the 5x+4y=-30 equation and you'll get 5(-6+3y)+4y=-30. Use the distributive property and you'll get -30+15y+4y=-30. Simplify and get -30+19y=-30, then add 30 to both sides and you'll get 19y=0. Divide by 19 on both sides and you'll get y=0. Now that we know y=0, plug that back into the 5x+4y=-30 equation, and you'll get 5x+4(0)=-30. Simplify and you'll get 5x=-30. Divide by 5 on both sides and you'll get x=-6.
If the juice is already at the tip of the straw when the thumb is released, initial velocity will be sqrt.2dg. Later on the flow is controlled by the partial vacuume created in the tube and it is indipendent of the d
