Answer:
x = 15
Step-by-step explanation:
As given, the equation 40 = 25 + x
As on the R.H.S of the equation, there is one constant and a variable x
As to isolate the variable we have to subtract the same constant so that that constant gives 0.
As we have the constant value 25
So, subtract 25 from both side of the equation, we get
40 - 25 = 25 + x - 25
⇒15 = x
∴ we get
x = 15
Answer:
-120 is a negative and 400 is a positive
Step-by-step explanation:
also there is a 520 difference
Answer:
The work is in the explanation.
Step-by-step explanation:
The sine addition identity is:
.
The sine difference identity is:
.
The cosine addition identity is:
.
The cosine difference identity is:
.
We need to find a way to put some or all of these together to get:
.
So I do notice on the right hand side the
and the
.
Let's start there then.
There is a plus sign in between them so let's add those together:

![=[\sin(a+b)]+[\sin(a-b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%2Bb%29%5D%2B%5B%5Csin%28a-b%29%5D)
![=[\sin(a)\cos(b)+\cos(a)\sin(b)]+[\sin(a)\cos(b)-\cos(a)\sin(b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%29%5Ccos%28b%29%2B%5Ccos%28a%29%5Csin%28b%29%5D%2B%5B%5Csin%28a%29%5Ccos%28b%29-%5Ccos%28a%29%5Csin%28b%29%5D)
There are two pairs of like terms. I will gather them together so you can see it more clearly:
![=[\sin(a)\cos(b)+\sin(a)\cos(b)]+[\cos(a)\sin(b)-\cos(a)\sin(b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%29%5Ccos%28b%29%2B%5Csin%28a%29%5Ccos%28b%29%5D%2B%5B%5Ccos%28a%29%5Csin%28b%29-%5Ccos%28a%29%5Csin%28b%29%5D)


So this implies:

Divide both sides by 2:

By the symmetric property we can write:
