That is false the opposite of 7 is -7
The given expression is

And in the second factor, x is common. So on taking x out, we will get

We can expand it by distributing , that is


Combining like terms,

And that's the expanded form ., and the given expression can also be written in that way .
Answer:
5..(b)
Step-by-step explanation:
Pythagoras theorem states that
Hypotenuse(squared)=opposite(squared)+ adjacent(squared)
hypotenuse=?,opposite=3,adjacent=4
hyp(squared)=3(squared)+4(squared)
hyp(squared)=9+16
hyp(squared)=25
find the square root of both sides
hypotenuse=5
Since we don't want to use the Pythagorean Theorem on all of these, first we look for some Pythagorean Triples. Its very helpful to know some of the common ones, so here's a list:
3, 4, 5
5, 12, 13
7, 24, 25
8, 15, 17
So we either look for these or a multiple of these numbers.
The last one is the only one that fits because 15, 20, 25 is a multiple of the triple 3, 4, 5 by multiplying all of them by 5.
Thus, 15, 20, 25 forms a right triangle.