To solve this system of equations using substitution, what could be substituted in place of y in the first equation?
4x=5-2y
y-2x = 7
OA 7-21
B. 41 - 5
• D. 20 +7

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.