1) plug in 1 for x to get the following:
1^2 + 2(1)
1^2 = 1
2 * 1 = 2
1 + 2 = 3
the answer is 3.
2) for estimating, your teacher may have another method but here's how i was taught:
determine whether to round up or down to a whole number:
7.9 rounds up to 8 and 0.67 rounds up to 1, and 8 * 1 is 8, so i would estimate the answer to be 8.
(i can't do the remaining two sorry!!)