2*(500-у/3)=820 :реши уравнение 60*(у/40+4)=720 (60*а-30)/5=18

1.  [latex]2(500-\frac{y}{3})=820[/latex] [latex]1000-\frac{2y}{3}=820[/latex] [latex]-\frac{2y}{3}=820-1000[/latex] [latex]-\frac{2y}{3}=-180[/latex] [latex]-2y=-180*3[/latex] [latex]-2y=-540[/latex] [latex]y=270[/latex] – [latex]2(500-\frac{270}{3})=820[/latex] [latex]2(500-90)=820[/latex] [latex]2*410=820[/latex] 2.  [latex]60(\frac{y}{40}+4)=720[/latex] [latex]\frac{60y}{40}+240=720[/latex] [latex]1,5y=720-240[/latex] [latex]1,5y=480[/latex] [latex]y=\frac{4800}{15}[/latex] [latex]y=320[/latex] – [latex]60(\frac{320}{40}+4)=720[/latex] [latex]60(8+4)=720[/latex] [latex]60*12=720[/latex] 3.  [latex]\frac{60a-30}{5}=18[/latex] [latex]60a-30=18*5[/latex] [latex]60a-30=90[/latex] [latex]60a=90+30[/latex] [latex]60a=120[/latex] [latex]a=2[/latex] – [latex]\frac{120-30}{5}=18[/latex] [latex]\frac{90}{5}=18[/latex]