Alonzo bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $400 more than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was 7% per year, and for the laptop it was
8% per year. The total finance charges for one year were $275 . How much did each computer cost before finance charges

x = price of desktop computer (dollars)
y = price of laptop computer (dollars)

y = x + 400
x * 0.07 + y * 0.08 = 275

x * 0.07 + (x + 400) * 0.08 = 275
0.07x + 0.08x + (400 * 0.08) = 275
0.15x + 32 = 275
0.15x = 275 - 32
0.15x = 243
x = 243 / 0.15
x = 1620

y = 1620 + 400
y = 2020

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