Well I don't know where inequalities would come in but the third length would be solved as follows.
a^2+b^2=c^2
10^2+18^2=424

Answer;

I hope this is correct, its what I would do if I had this equation.
Answer:
Answer is in the explanation
Step-by-step explanation:
I don't know exactly word from word what your choices look like...
but I can describe per each box what happened in my own words:
First box: They multiply first equation by 3 and the second equation by 2 to obtain the equations in that first box.
Second box: They subtracted the two equations in the first box to obtain 1x+0y=2 which means 1x=2 or x=2 (this is called solving a system by elimination
Third box: They used their first original equation (before the multiplication manipulation) and plug in the value they got for x which was 2 giving them 3(2)-2y=10
Fourth box: They simplified the equation 3(2)-2y=10 by performing the multiplication 3(2) giving them 6-2y=10
Fifth box: They subtracted 6 on both sides giving them -2y=4
Sixth box: They divided both sides by -2 giving them y=-2
I will summarize then what I wrote above:
1st box: Multiplication Property of Equality
2nd box: Elimination
3rd box: Substitution (plug in)
4th box: Simplifying
5th box: Subtraction Property of Equality
6th box: Division Property of Equality
The average yearly growth rate of the height of the tree was 2.2 feet per year during the 7 1/2 years.
Hi
4x-y=5
3x-7=2
We need to solve 3x-7=2 for x
Let's start by adding 7 to both sides
3x-7+7=2+7
3x=9
Now just divide both sides by 3 so we can find the value for x
3x/3=9/3
x=3
Now substitute 3 for x in 4x-y=5
4x-y=5
(4)(3)-y=5
-y+12=5
Now add -12
-y=12-12=5-12
-y=-7
Divide both sides by -1 so we can eliminate the negative sign
-y/-1=-7/-1
y=3
The answer is A
(3,7)
I hope that's help:0