In the second equation of Example 4, if − is replaced with +, what is the solution?

Data from Example 4

Solve the system of equations
2x + 5y = 10

3x - y =6
We could write each equation in slope-intercept form in order to sketch the lines. Also, we could use the form in which they are written to find the intercepts. Choosing to find the intercepts and draw lines through them, let y = 0; then x = 0. Therefore, the intercepts of the first line are the points (5, 0) and (0, 2). A third point is (−1, 12/5) The intercepts of the second line are (2, 0) and (0, −6). A third point is (−1, −3). Plotting these points and drawing the proper straight lines, we see that the lines cross at about (2.3, 1.1). [The exact values are (40/17, 18/17).] The solution of the system of equations is approximately x = 2.3, y = 1.1 (see Fig. 5.17).

Checking, we have

Transcribed Image Text:

2(2.3) + 5(1.1) 10.1 10 and 3(2.3) - 1.16 10 5.8 6