a)
[tex]4 + 5x - 2 = 7x - 7 \\ - 2x = 5 \\ x = - 2.5[/tex]
[tex]4 + 5 \times ( - 2.5) - 2 = 7 \times ( - 2.5) - 7 \\ 4 - 12.5 - 2 = - 17.5 - 7 \\ - 10.5 = - 10.5 \\ L = P[/tex]
b)
[tex] - 8 + 7x + 3 = 5x + 4 + 4x + 5 \\ - 2x = 14 \\ x = - 7[/tex]
[tex] - 8 + 7 \times ( - 7) + 3 = 5 \times ( - 7) + 4 + 4 \times ( - 7) + 5 \\ - 8 - 49 + 3 = - 35 + 4 - 28 + 5 \\ - 54 = - 54 \\ L = P[/tex]
