(a)
So here's the information we know:
Tanya bought 3 items
Tony bought 4 items
Tony's items were all 2.50 less than Tanya's
So, our equation should look like this:
3x = 4(x - 2.25)
(b)
3x = 4(x - 2.25)
3x = 4x - 9
-x = -9
x = 9
Tanya spent = 9 (x)
Tony spent = 6.75 (x - 2.25)
(c)
3(9) = 4((9) - 2.25)
27 = 36 - 9
27 = 27
or
Tanya: 3x = 3 (9) = 27
Tony: 4( x - 2.25) = 4(9-2.25) = 4(6.75) = 27
(d)
We can conclude that Tanya bought 3 items with a cost of $9 each, and Tony bought 4 items with a cost of $6.75 each. Both Tanya and Tony spent a total of $27.