Question

Pls ex 20 si 18 dau coroana

Answer 1

20. a x b x c + 5=19 => a x b x c =14 => ab+bc=14 /:b => a+c=14 => ac=14=> ac=7 => a x b x c = 14=> b= 14:7 => b=2
a + 2 x b +3 x c = 19=> a + 4+3 x c = 19 => a+3 x c = 15 => a+3c =15 =>a x (b +3c)= ab+ 3ac => a(2+3) x c = a x 5 x c = 15 => c= 3
a+ 4+9=19=> a= 6