Answer:
a. the first and last one
b. the second and third one
Step-by-step explanation:
a. 11x-3x-10x=18x, so the first one is definitely the answer. If you look at the last one, you can see that 10x+8x also equals 18x. The other options do not equal 18x, so those can be eliminated.
b. If you distribute the 3 outside of the parentheses, you can see that the expression 3(1+3y) equals 3+9y (because 3*1=3 and 3*3y=9y). So, the third one can be determined to be one of the answers. We can see that the second one also simplifies to be 3+9y, so this one can also be determined to be the answer. The other ones can be eliminated because they do not equal 3+9y.
Hope this helped! :)
