[tex]a) \\ \\ 11 + 18 \times x = - 10 \times x + 22 = 18 \times x + x \times 10 = 22 - 11 \\ \\ 28 \times x = 11 \\ \\ x = \frac{11}{28} \\ \\ b) \\ \\ 402 + 123 \times x = 40 \times x - 72 \\ \\ 123 \times x - x \times 40 = - 72 + 402 \\ \\ 83 \times x = - 474 \\ \\ x = - 5 \frac{59}{83} [/tex]
