collect like terms;
3x-10x=-7x
-7x+5=5x+17
move the variable to the left and change sign
-7x+5=5x+17
move the constant to the right and change sign
-7x-5x+17-5
collect the like terms
-12x=17-5
subtract the numbers
-12x=12
divide both sides by -12
your answer is: x= -1