Question 1201087
.


In this my post, I will prove part (1), ONLY.



<pre>
    Let's assume that 3x-5 = 10.

    Then  3x = 10+5 = 15,  which implies  x = 15/3 = 5.

    But we are given that x=2;  hence, we got a contradiction.


    Thus, our assumption  3x-5 = 10 leads to the contradiction;
    hence,  3x-5≠10.  QED.
</pre>

Solved.