All exercises involve the same concept, so I'll show you how to do the first, then you can apply the exact same logic to all the others.
The first thing you need to know is that, when a certain quantity multiplies a parenthesis, you can distribute that number to every element in the parenthesis. This means that
So, 
is multiplying the parenthesis involving 
and 
, and we distributed it: multiplies both and in the final result.
Secondly, you have to know how to recognize like terms, because they are the only terms you can sum. Two terms can be summed if they have the same literal expression. So, for example, you cannot sum 
, and neither 
exponents count.
But you can su, for example,
or
So, take for example exercise 9:
We distribute the 1.2 through the first parenthesis:
And you can distribute the negative sign through the second parenthesis (it counts as a -1 to distribute):
So, the expression becomes
Now sum like terms:
70 - 3 = 67 emojis
67 - 26 = 41 emojis
41 emojis have thumbs up.
Answer:
If something has stripes it is not always a zebra but a zebra always has stripes
Step-by-step explanation:
Many things have stripes and aren't called zebras
Some primitive triples are ...
(3, 4, 5)
(5, 12, 13)
(7, 24, 25)
(9, 40, 41)
One interesting characteristic of these is that the sum of the last two numbers is the square of the first number.
Any multiple of these will be a Pythagorean triple.
Now consider your list.
a) (10, 24, 26) = 2×(5, 12, 13) . . . IS a Pythagorean Triple
b) 2×(7, 24, 25) = (14, 48, 50), so (14, 48, 49) is NOT a Pythagorean Triple
c) 3×(3, 4, 5) = (9, 12, 15), so (9, 12, 16) is NOT a Pythagorean Triple
d) (9, 40, 41) . . . IS a Pythagorean Triple
e) 5×(3, 4, 5) = (15, 20, 25) . . . IS a Pythagorean Triple
The sets of side lengths that are Pythagorean Triples are ...
(10, 24, 26)
(9, 40, 41)
(15, 20, 25)
