Answer:
A linear equation has the greatest x power at 1.
If you see an equation with only x (no x^2 or x^3 or stuff like that), you will know that it is linear.
The slope-point form of a line:

The slope-intercept form of a line:

1.

Substitute

2.

Substitute

3.

4.

Complete the Square:
Plug your numbers in this function
You get this
That equals 
Answer:
m∠Q = 121°
m∠R = 58°
m∠S = 123°
m∠T = 58°
Step-by-step explanation:
The sum of the interior angles of a quadrilateral = 360°
Create an expression for the sum of all the angles and equate it to 360, then solve for x:
∠Q + ∠T + ∠S + ∠R = 360
⇒ 2x + 5 + x + 2x + 7 + x = 360
⇒ 6x + 12 = 360
⇒ 6x = 360 - 12 = 348
⇒ x = 348 ÷ 6 = 58
So now we know that x = 58, we can calculate all the angles:
m∠Q = 2x + 5 = (2 x 58) + 5 = 121°
m∠R = x = 58°
m∠S = 2x + 7 = (2 x 58) + 7 = 123°
m∠T = x = 58°