1)x+30=40
x=40-30
Answer :x=10
2)30-20+2x=10
10+2x=10
2x=0
Answer: x=0
3)3x-10+13=-2x+28
3x+3=-2x+28
3x+2x+3=28
3x+2x=28-3
5x=28-3
5x=25
x=5
4)13x-23-45=-7x+12
13x-68=-7x+12
13x+7x-68=12
13x+7x=12+68
20x=12+68
20x=80
x=4
5)2(x+4)=10x+24
2x+8=10x+24
2x-10x+8=24
2x-10x=24-8
-8x=24-8
-8x=16
x=-2
6)3(x-5)=1-(2x-4)
3x-15=1-(2x-4)
3x-15=1-2x+4
3x-15=5-2x
3x+2x-15=5
3x+2x=5+15
5x=5+15
5x=20
x=4
7)5x-10=15
5x=15+10
5x=25
x=5
8)x+4=x+6
4=6
no solution
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<h2>
Answer and Explanation to questions 13,14,15</h2>
13)
as given in the question.
14)
Since Y is the midpoint of XZ. So, Y will divide XZ in equal halves into XY and YZ.
15) 
and
. So, 
<h2>
Answer and Explanation to questions 16,17,18</h2>
∠3 is supplementary to ∠1 means: ∠3 + ∠1 = 180°
And, according to figure ∠1 + ∠2 = 180° as ∠1 and ∠2 form a straight line.
∠3 + ∠1 = 180° .............(i)
∠1 + ∠2 = 180° .............(ii)
subtracting equation (i) and (ii) will give ∠3 = ∠2 ..........(iii)
15) ∠3 is supplementary to ∠1 as given in the question
16) ∠2 is supplementary to ∠1 as shown be equation (ii)
18) ∠3 ≅ ∠2 as shown by equation (iii)
<h2>
Answer and Explanation to questions 19</h2>
∠3 and ∠4 form a straight line. Therefore, ∠3 + ∠4 = 180° .......(i)
∠4 and ∠5 form a straight line. Therefore, ∠4 + ∠5 = 180° .......(ii)
subtracting equation (i) and (ii)
∠3 + ∠4 - (∠4 + ∠5) = 180°-(180°)
∠3 + ∠4 - ∠4 - ∠5 = 180°-180°
∠3 - ∠5 = 0
∴ ∠3 = ∠5 (Hence Proved)
Given:
A triangle ABC.
The given expression for b is:

To find:
The expression that is equivalent to b.
Solution:
According to the Law of Cosines,

It can be written as:
...(i)
We have,
...(ii)
On comparing (i) and (ii), we get




Therefore, the required values are
.
Answer:
x=-14
Step-by-step explanation:
30-(-16)=-30+16=-14=x
x=-14