10 Реши уравнения с комментированием по компонентам действай 400:t-32 = 48; б) 250 + 9· a = 520; в) (780 - m. 60): 6 = 70; г) 640 : (х9 + 8) = 8.

а)

• 400:t-32 = 48;
• 400:t = 48 + 32;
• 400:t = 80;
• t = 400 : 80;
• t = 5;

б)

• 250 + 9 ⋅ a = 520;
• 9 ⋅ a = 520 - 250;
• 9 ⋅ a = 270;
• a = 270 : 9;
• a = 30;

в)

• (780 - m ⋅ 60) : 6 = 70;
• 780 - m ⋅ 60 = 70 ⋅ 6;
• 780 - m ⋅ 60 = 420;
• -m ⋅ 60 = 420 - 780;
• -m ⋅ 60 = -360;
• m = -360 : (-60);
• m = 6;

г)

• 640 : (x ⋅ 9 + 8) = 8;
• x ⋅ 9 + 8 = 640 : 8;
• x ⋅ 9 + 8 = 80;
• x ⋅ 9 = 80 - 8;
• x ⋅ 9 = 72;
• x = 72 : 9;
• x = 8.