Answer:
a, b, c
(all but the last one)
Step-by-step explanation:
a+b+c=180 is true bcuz the sum of interior angles in a triangle is 180
rearrange a+b+c=180 into a+b=180-c
observe that 180-c equals d, so in the equation a+b=180-c replace 180-c with d.
a+b=d so thats true
we already established that d=180-c so thats true as well
and the last one is just not true
