a) 89 - (73 - x) = 20
73 - x = 89 - 20 = 69
x = 73 - 69 = 4
b) 140 : (x-8) = 7
x - 8 = 140 : 7 = 2
x = 8 + 2 = 10
\(a,89-\left(73-x\right)=20\\ 73-x=69\\ x=4\\ b,140:\left(x-8\right)=7\\ x-8=20\\ x=28\)
a) 89-(73-x)=20
73-x= 89-20
73-x=69
x=73-69
x= 4
b) 140:(x-8)=7
x-8=140:7
x-8=20
x = 20+8
x = 28
a, 89 - ( 73-x ) = 20
<=> 73 + x = 89 - 20
<=> 73 + x = 69
<=> x = 73 - 69
=> x = 4
b, 140 : ( x-8 ) = 7
<=> x - 8 = 140 : 7
<=> x - 8 = 20
<=> x = 20 + 8
=> x = 28