When you represent intervals on the number line, you're including full dots, excluding empty dots, and you're considering numbers highlighted by the line.
In the first case, you've highlighted everything before -2 (full dot, thus included), and everything after 1 (empty dot, excluded). So, the set would be
or, in interval notation,
![(-\infty,-2]\cup (1,\infty)](https://tex.z-dn.net/?f=%28-%5Cinfty%2C-2%5D%5Ccup%20%281%2C%5Cinfty%29)
In the second case, you are looking for all numbers between -3 and 5. This interval is symmetric with respect to 1: you're considering all numbers that are at most 4 units away from 1, both to the left and to the right.
This means that the difference between your numbers at 1 must be at most 4, which is modelled by
where the absolute values guarantees that you'll pick numbers to the left and to the right of 1.
The expansion of a perfect square is
In words, the square of a sum of two terms is the sum of the squares of the two terms (
and 
), plus twice the product of the two terms (
)
So, when determining if you have a perfect square trinomial, you should have two perfect squares. Note that they don't have to be the first and third term, since you can rearrange terms as you prefer.
Answer:
7 miles per hour
Step-by-step explanation:
3 1/2 miles = 7/2 miles
1/2 hours= 30 minutes
So,
In 30 mins, travelled 7/2 miles
In 1 min, travelled 7/2 ÷ 30= 7/2× 1/30 = (7×1)/(2×30) = 7/60 miles
In 60 mins, travelled (7×60)/60 miles = 420/60 miles = 7 miles.
Hence, the speed is 7 miles per hour.
Hope this helps :)
Two positives make a positive
two negatives make a positive
1 negative and 1 positive make negative
1 positive and 1 negative make a negative
