\(75:x=-15\\ x=\left(-75\right):15\\ x=-5\)
=> 75 : x = -15
=> x = 75 : (-15)
=> x = -5
\(75:x=5+\left(-20\right)\\ \Rightarrow75:x=-15\\ \Rightarrow x=75:\left(-15\right)\\ \Rightarrow x=-5\)
75 : x = 5 + (-20)
<=> 75 : x = - 15
<=> x = 75 : (-15)
<=> x = - 5