C-12-Q056mediumsingle_mcqBy cross-multiplication, the value of yyy is —ab1c2−b2c1a1b2−a2b1\dfrac{b_1 c_2 - b_2 c_1}{a_1 b_2 - a_2 b_1}a1b2−a2b1bc1a2−c2a1a1b2−a2b1\dfrac{c_1 a_2 - c_2 a_1}{a_1 b_2 - a_2 b_1}a1b2−ca1b2−a2b1c1a2−c2a1\dfrac{a_1 b_2 - a_2 b_1}{c_1 a_2 - c_2 a_1}c1a2−dc1a2−c2a1b1c2−b2c1\dfrac{c_1 a_2 - c_2 a_1}{b_1 c_2 - b_2 c_1}b1c2−