Solutions To Mathematics Textbooks/Basic Mathematics/Chapter 2

=Chapter 2=

11
$$ax + by = u\,$$

$$cx + dy = v\,$$

$$acx + bcy = uc\,$$

$$acx + ady = va\,$$

$$(acx + bcy)-(acx + ady) = uc - va\,$$

$$bcy - ady = uc - va\,$$

$$y(bc - ad) = uc - va\,$$

$$y = \frac{uc-va}{bc-ad}$$