Find the slope of the lines

first pic question 1
a) -2
b) - 1/2
c) 1/2
d)1

second pic question 2
a) 1/2
b) -2/7
c) 2
d) 1/2

third pic question 3
a) -3/2
b)-2/3
c) 3/5
d)2/3

will give brainlist < plz hurry twt

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.