Create an equivalent system of equations using the sum of the system and the first equation.
−3x + y = 12
x + 3y = 6
a.−3x + y = 12
−2x + 4y = 18
b.−3x + y = 12
−3x + 4y = 18
c.−3x + y = 12
x + 4y = 18
d.−3x + y = 12
−2x + 4y = 6

Seth practice piano for 1 1/3 hours on saturday and 5/6 hour on sunday for much longer did he practice on saturday than on sunday?

Aflower has 26 chromosomes. to create a new flower, how many chromosomes would a sperm cell have? what is this process called? part 2: within a flower cell that has 26 chromosomes, how many chromosomes would a cell that is created within the stem of a flower as it grows, have? what is this process called?

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