Answer:
The pairs are (13,15) and (-15,-13).
Step-by-step explanation:
If n is an odd integer, the very next odd integer will be n+2.
n+1 is even (so we aren't using this number)
The sum of the squares of (n) and (n+2) is 394.
This means
(n)^2+(n+2)^2=394
n^2+(n+2)(n+2)=394
n^2+n^2+4n+4=394 since (a+b)(a+b)=a^2+2ab+b^2
Combine like terms:
2n^2+4n+4=394
Subtract 394 on both sides:
2n^2+4n-390=0
Divide both sides by 2:
n^2+2n-195=0
Now we need to find two numbers that multiply to be -195 and add up to be 2.
15 and -13 since 15(-13)=-195 and 15+(-13)=2
So the factored form is
(n+15)(n-13)=0
This means we have n+15=0 and n-13=0 to solve.
n+15=0
Subtract 15 on both sides:
n=-15
n-13=0
Add 13 on both sides:
n=13
So if n=13 , then n+2=15.
If n=-15, then n+2=-13.
Let's check both results
(n,n+2)=(13,15)
13^2+15^2=169+225=394. So (13,15) looks good!
(n,n+2)=(-15,-13)
(-15)^2+(-13)^2=225+169=394. So (-15,-13) looks good!
Test the choices !
Pick an even number, and see what each choice does to it.
Let's start with, say, 6 .
We'll try each choice, and see which one produces an odd number:
a). 6 to the 2nd power. . . . . . 6 x 6 = 36. That's not an odd number.
b). 6 + 3 = 9 This could be it. 9 is odd. We'll save this one.
c). 3·6 = 18. That's not an odd number.
d). 6/3 = 2. That's not an odd number.
The only one that gave us an odd number is (b).
Answer:
x=1/5
Step-by-step explanation:
To solve this question we will have to open the bracket first
So let's go back to the given question
-2(5x-1)+7(5x-1)-3(-5x+1)
We can actually equate the equation to zero
Let's solve
-10x+2+35x-7+15x-3=0
Let's collect like terms
-10x+35x+15x=-2+7+3
40x=8
Let's make x the subject of formula by dividing both sides by 40
x=1/5
So the final answer is 1/5
Just plug in 3 for n and then 5 for n to see if an turns out to be 10 and 26.
n=3:
A) an = 8*3+10 = 34
B) an = 8*3 - 14 = 10 OK
C) an = 16*3+10 = 58
D) an = 16*3 - 38 = 10 OK
n=5:
B) an = 8*5-14 = 26 OK
D) an = 16*5 - 38 = 42
So the answer is B
