Answer:
=3.162
Step-by-step explanation:
x2
= −0 + √ 02 − 4×1×(−10)
2×1
= 0 + 2 × √ 10
2
= 3.162
1. 13*13*13 =2197
2. 2/5*2/5 = 4/25
3. 0.9*0.9 = 0.81
Let's begin by listing out the information given to us:
There are four students: n = 4
Number of students to be selected: r = 2
To calculate the combination of 2 students to be chosen, we use:

Therefore, there 12 possible combinations from these
We know that
We can write an Arithmetic Sequence as a rule:
<span>an = a1 + d(n−1)</span>
where
<span>a1 = the first term
<span>d =the "common difference" between terms
in this problem
a1=15 a2=7 a3=-1 a4=-9 ..... an=-225
d=a2-a1
d=7-15-----> d=-8
</span></span>an = a1 + d(n−1)
for
an=-225
d=-8
a1=15
find n
-225=15+(-8)*(n-1)--> (n-1)=[-225-15]/-8----> n-1=30---> n=30+1---> n=31
the answer is31