We know that the calculator price (x) was 25 more than 3 times the price of the textbook (y).
This can be represented as:
[tex]x=3y+25[/tex]We also know that the sum of the prices of the two items is equal to $165:
[tex]x+y=165[/tex]We have to solve this system of equations with the method of substitution.
We can use the first equation, as we have already clear the value of x, to substitute x in the second equation and then solve for y:
[tex]\begin{gathered} x+y=165 \\ (3y+25)+y=165 \\ 4y+25=165 \\ 4y=165-25 \\ 4y=140 \\ y=\frac{140}{4} \\ y=35 \end{gathered}[/tex]With the value of y we can calculate x using the first equation:
[tex]\begin{gathered} x=3y+25 \\ x=3\cdot35+25 \\ x=105+25 \\ x=130 \end{gathered}[/tex]Answer: the solution as ordered pair is (x,y) = (130, 35)
