Answer:
They charged $6 for washing and $2 for vacuuming the car.
Step-by-step explanation:
Let the charge of washing a car be 'x'.
And also let the charge of vacuuming a car be 'y'.
Now according to question, Trisha raised $38 washing 5 cars and vacuuming 4 cars.
So framing the above sentence in equation form, we get;
[tex]5x+4y=38\ \ \ \ \ equation\ 1[/tex]
Again according to question, Byron raises $28 by washing 4 cars and vacuuming 2 cars.
So framing the above sentence in equation form, we get;
[tex]4x+2y=28\ \ \ \ \ equation\2[/tex]
Now multiplying equation 2 by '2', we get;
[tex]2(4x+2y)=28\times2\\\\8x+4y=56\ \ \ \ equation\ 3[/tex]
Now we subtract equation 1 from equation 3 and get;
[tex](8x+4y)-(5x+4y)=56-38\\\\8x+4y-5x-4y=18\\\\3x=18\\\\x=\frac{18}{3}=6[/tex]
Now substituting the value of 'x' in equation 1, we get;
[tex]5x+4y=38\\\\5\times6+4y=38\\\\30+4y=38\\\\4y=38-30=8\\\\y=\frac{8}{4}=2[/tex]
Hence They charged $6 for washing and $2 for vacuuming the car.