*Please don’t answer if you are going to put a link, they don’t work* Hey! I have 3 algebra problems and it would be greatly appreciated if you could add the answers in the text box or photo! Thank you so so much:)

Can someone me with my hwplz(only the circled ones)

Which value of m will create a system of parallel lines with no solution? y = mx - 6 8x - 4y = 12

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.