3.) r=2: 2+4/15= 6/15=2/5
2.) -3a-15=a: the fraction is negative. meaning the answer is negative, leaving a and c as choices. You can't square a since it is on different sides of the equation leaving you with c.
1.) answer is 5(x+4)=30: 3 is 2, meaning you would use the 2.
