Opposite angle of a quadrilateral add up to 180 degrees.
This means Angle A plus Angle C equal 180.
We can solve for X using that, then solve for Angle B.
2x-7 + x +4 = 180
Simplify:
3x -3 = 180
Add 3 to each side:
3x = 183
Divide both sides by 3:
x = 183 /3
x = 61
Now we know x, replace x with 61 in the equation for Angle B:
Angle B = 2x+3 = 2(61) +3 = 122 +3 = 125 degrees.
