Let x be cost of one daylily and y be the cost of one scrub.
Ashley spent $45 on 7 daylilies and 2 shrubs. 7 daylilies cost 7x and 2 shrubs cost 2y, in total 7x+2y that is $45. The first equation is 7x+2y=45.
Lisa spent $174 on 14 daylilies and 11 shurbs. 14 daylilies cost 14x and 11 shrubs cost 11y, in total 14x+11y that is $174. The second equation is 14x+11y=144.
Solve this system. Wit hthis aim multiply first equation by 2 and the subtract second equation from first:
2·(7x+2y)-(14x+11y) =2·45-174,
14x+4y-14x-11y=90-174,
-7y=-84,
7y=84,
y=84÷7,
y=12.
Then substitute into first equation:
7x+2·12=45,
7x+24=45,
7x=45-24,
7x=21,
x=21÷7,
x=3.
Answer: the cost of one daylily is $3 and the cost of one scrub is $12.