Trinomes in equations write as square binomials (square sums and square differences), and then solve the equations​

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

What is the solution to the system of equations below? y=-1/3x+6 and y= 1/3x-6ono solutioninfinitely many solutions(-18, 12)(18,0)

Minixa counted 40 green cars, and 20 sliver cars in the parking lot. if the number of green cars stay the same, how many more silver cars would need to be added so the ratio of green cars to silver cars is 1 to 3?