.
= 5.
Square both sides. You will get
7 - 3x =
, or, which is the same
7 - 3x = 25.
Add 3x to both sides. You will get
7 = 25 + 3x, or, which is the same,
25 + 3x = 7.
Distract 25 from both sides. You will get
3x = 7 - 25, or, which is the same
3x = -18.
Divide both sides by 3. You will get
x =
= -6.
Answer. x = -6.
Check.
=
=
= 5. Checked !