Question

Solve for xAn explanation would be great.

Answer 1

When two lines intersect, (in this case it's a ray and a line), they form a linear pair. Here, we know that $93+3x+18=180$ because those two angles form a linear pair. Solving for x we have :

$111+3x=180 \implies \\ 3x=69 \implies \\ x=23$

Answer 2

The angle is a straight angle. Straight angles measure 180°. One of the angles measures 93°. Subtract 93 from 180.

$180 - 93 = 87$

That means:

$3x + 18 = 87$

Switch it around and it becomes:

$87 - 18 = 3x$

The sign changes when you move it to the other side. at first you were adding, and now you're subtracting.

Subtract:

$87 - 18 = 69 \\ 3x = 69$

Divide both sides by 3 to leave the variable alone:

$3x \div 3 = x \\ 69 \div 3 = 23$

That means x = 23