1.22. Теңдеулерді шешіңдер. 1) 0,12 − 2,5x = −0,8; 2) 4,8x − 0,8 = 4,2 · 0,5; 3) 1 3/4 − 5x = 2 3/4 · (−3 2/3); 4) 20x + 0,4 · (−6 1/4) = 4 2/3 · (−2 1/7).

1) \(0.12-2.5x=-0.8\).

\(-2.5x=-0.92\), сондықтан \(x=0.368\).

2) \(4.8x-0.8=4.2\cdot0.5=2.1\).

\(4.8x=2.9\), сондықтан \(x=\frac{2.9}{4.8}=\frac{29}{48}\).

3) \(1\frac34-5x=2\frac34\cdot\left(-3\frac23\right)\).

\(\frac74-5x=\frac{11}{4}\cdot\left(-\frac{11}{3}\right)=-\frac{121}{12}\).

\(-5x=-\frac{121}{12}-\frac74=-\frac{71}{6}\), сондықтан \(x=\frac{71}{30}\).

4) \(20x+0.4\cdot\left(-6\frac14\right)=4\frac23\cdot\left(-2\frac17\right)\).

\(20x-\frac52=-\frac{14}{3}\cdot\frac{15}{7}=-10\).

\(20x=-\frac{15}{2}\), сондықтан \(x=-\frac38\).

Жауап: 1) \(x=0.368\); 2) \(x=\frac{29}{48}\); 3) \(x=\frac{71}{30}\); 4) \(x=-\frac38\).