The first one in incorrect , it should be 130 but the rest are correct !
Factor the polynomial:
4u² – 20u + 25
Rewrite – 20u as – 10u – 10u, and then factor it by grouping:
= 4u² – 10u – 10u + 25
= 2u * (2u – 5) – 5 * (2u – 5)
= (2u – 5) * (2u – 5)
= (2u – 5)² <––– this is the answer.
I hope this helps. =)
A proportion looks like this:

It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion

And then solve it for x:

Answer:
x = ± 10
Step-by-step explanation:
Given
x² - 100 = 0 ( add 100 to both sides )
x² = 100 ( take the square root of both sides )
x = ±
← note plus or minus, hence
x = ± 10
Answer:
0
Step-by-step explanation:
The only value that would make sense is if at least one of the variables (A , B , C , D) is 0 (if not all of them). When multiplied, the answer will still be 0, thereby making the equation true.
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