Henrietta is planting a new flower garden. she must have yellow and red rosebushes. let x represent the number of yellow rosebushes and y represent the number of red rosebushes. she wants at least 4 times as many yellow rosebushes as red rosebushes. each yellow rosebush costs $7.50 and each red rosebush costs $4.75. she can spend no more than $125.

From the problem statement, we have two unknowns which are 

x = yellow rosebushes
y = red rosebushes

To be able to determine the number of each rosebushes she can buy, we need to set up two equations from the given values. We set up these equations as follows:

For the first equation, we make use of the statement:

She wants at least 4 times as many yellow rosebushes as red rosebushes. 
x = 4y

For the second equation, we use the statement of the prices and her maximum cost,

125 = 7.50x + 4.75y

We can now solve for x and y,
125 = 7.50(4y) + 4.75y
125 = 34.75y
y = 3.6
x = 14.4

Therefore, she should be able to buy up to about 4 yellow rose bushes and 14 red rosebushes.

X≥4y  y>0  7.50x+4.75y≤125  x>0