Question

5/12a+3/4a-1/2a и найдите его значение при a = 2,1

Answer 1

$\frac5{12}a+\frac34a-\frac12a=\frac5{12}+\frac9{12}a-\frac6{12}a=\frac{14}{12}a-\frac6{12}a=\frac8{12}a=\frac23a\\a=2,1=2\frac1{10}=\frac{21}{10}\\\frac23a=\frac23\cdot\frac{21}{10}=\frac75=1\frac25$