I love maths! need help?

Ifurniture stores having a weekend sale and is offering 20% discount on patio chairs and table the sales tax on furniture is 6.25 using function composition how can you represent the total amount a that you would need to pay for this furniture that cost x dollars

Solve: 3x+y=6 4x-2y=18 show all work !

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?