Remember you can do anything to an equation as long as you do it to both sides
2x+3(x-4)=x-20
first distribute
2x+3(x)+3(-4)=x-20
2x+3x-12=x-20
5x-12=x-20
minus x both sides
4x-12=-20
add 12 to both sides
4x=-8
divide both sides by 4
x=-2
Multiply:
2 boxes x 5 packs each = 10 total packs
10 packs x 8 markers per pack = 80 total markers
Any: 80 markers
Answer:
The directrix is y=6 and focus is (0,4)
The equation of the parabola is,
20-4y=x²