Answer:
-2 < x < 2
Step-by-step explanation:
Answer:
176/231
Step-by-step explanation:
88 blue marbles, 55 green marbles, and 88 red marbles =231 marbles
P (blue or red marble) = number of red or blue/ total
= 88+88 / 231
=176/231
X:2+(105-275:11):4=28
X:2+(105-25):4=28
X:2+80:4=28
X:2+20=28
X:2=28-20
X:2=8
X=8×2
X=16
Let's start from what we know.

Note that:

(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first

with only positive trems (squares of even numbers) and second

with negative (squares of odd numbers). So:

And now the proof.
1) n is even.
In this case, both

and

have

terms. For example if n=8 then:

Generally, there will be:

Now, calculate our sum:



So in this case we prove, that:

2) n is odd.
Here,

has more terms than

. For example if n=7 then:

So there is

terms in

,

terms in

and:

Now, we can calculate our sum:




We consider all possible n so we prove that:
Answer:
3−y
2. 8
4.2bh
Step-by-step explanation:
5(2x+y)=15
2 Divide both sides by 55.
2x+y=\frac{15}{5}2x+y=
5
15
3 Simplify \frac{15}{5}
5
15
to 33.
2x+y=32x+y=3
4 Subtract yy from both sides.
2x=3-y2x=3−y
5 Divide both sides by 22.
x=\frac{3-y}{2}x=
2
1. 3−y
2. 8
2.Add 2y2y to both sides.
x=-8+2yx=−8+2y
2 Regroup terms.
x=2y-8x=2y−8