Y=-2x+6 3y-x+3=0 solving systems using substitution

Which of the binomials below is a factor of this trinominal? x^2-13+30

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost