My little cuz need help can you help her please Its Eight grade math

Solve the equation by using substitution

4x-2y=18
y=5x

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

Mis the midpoint of rq if rm equals 2x + 5 and mq equals 4x - 9 what is the length of rq

Point r divides in the ratio 1 : 5. if the coordinates of e and f are (4, 8) and (11, 4), respectively, what are the coordinates of r to two decimal places?