Okay, for this one is will use substitution:
y=x+4
y-x=4
2y-2x=8
-2x+2y=8
+
2x+y=13
=
3y=21
y=7
x=3 is your final answer. Hope it help!
The answer for this problem is 6+4x
Answer:

Step-by-step explanation:
Given:
Angle of elevation = 70°
Length of string = 68 m
We need to find the height of the kite.
Solution:
Requirement figure attached in file.
Where:
BC = 68 m
AC = h (Height of the kite)
∠ABC = 70°
Using Cosine rule to find the height of the kite.



Therefore, height of the kite from Brian's head
.
How to get answer:
Craigs, percent = difference/original = (7 - 4)/4 = 3/4 = 75%.
The argument is valid by the law of syllogism