7x+10=59

10-7x+10=59-10
3x+10=49
???

-3+x=5
3+(-3)+x=5+3
x=8
Is this right Ms.Sue?

Although I am not Ms.Sue:

7x+10=59

7x does not change to a negative.

7x + 10 - 10 = 59 -10

7x = 49

x = 7