Because the triangle is isosceles, angle P and angle R are the same. Thus, your work would be:
. You then simplify this to 6x+4 + 196 - 8x = 180. Combine like terms, you get - 2x = - 20. x = 10.
Plug x = 10 back into the equation 98 - 4x to get 98 - 4(10) which becomes 98 - 40 = 58.
Angle P should be equal to 58 degrees.
To check your work add up the angles to see if they equal 180:
58 + 58 + 6(10) + 4 = 116 + 64 = 180.