Решите рационально 3 12/19 × 4 3/23 + 1 4/19 × 5 7/23 - 1 8/19

3 12/19*4 3/23+ 1 4/19*5 7/23- 1 8/19=69/19*95/23+23/19*122/23-(27*23)/(19*23)= = 23*3*95+23*122-27*23 = 23*(3*5*19+122-27) = 15*19+95 = 19(15+5) =20              19*23                          19*23                    19              19

[latex] \frac{69}{19} * \frac{95}{23}+ \frac{23}{19} *5[/latex] [latex]1) \frac{69}{19} * \frac{95}{23} = \frac{69*95}{19*23} = \frac{6555}{437} =15[/latex] [latex]2) \frac{23}{19} *5= \frac{23}{19} * \frac{5}{1} = \frac{115}{19} =6 \frac{1}{19} [/latex] [latex]3) 15+ 6\frac{1}{19} = \frac{15}{1} + \frac{115}{19} = \frac{15*19}{1*19} + \frac{115}{19} = \frac{285}{19} + \frac{115}{19} = \frac{400}{19} =21 \frac{1}{19} [/latex]