Well first you have to add common like terms in this case 2r and -6r to get -4r now your equation is -4r+8=40, now subtract 8 from both sides to leave r by itself and get -4r=32, now divide both sides by -4 to get r=-8
Hope this helps
In a triangle, the three interior angles always add to 180°
m∠B = 180 - 30 - 80 = 70°
<span>D: 70</span>
What part do you not understand?
