Omg i would just guess and go for the third one
Answer:
First i always use khan academy
Step-by-step explanation:
x = 43, AB = 49, BC = 49 and AC =98.
Solution:
Given data:
AC = 3x - 31 and AB = x + 6
B is the midpoint of AC.
Therefore AB = BC
.
BC = x + 6
AB + BC = AC
x + 6 + x + 6 = 3x - 31
2x + 12 = 3x - 31
Add 31 on both sides, we get
2x + 43 = 3x
Subtract 2x from both sides, we get
43 = x
AB = x + 6
= 43 + 6
AB = 49
BC = 49
AC = 3x - 31
= 3(43) - 31
= 129 - 31
AC = 98
Therefore x = 43, AB = 49, BC = 49 and AC =98.
When you multiply the first equation by 3, you get:
3 × 3x = 9x
3 × y = 3y (but when added, that part gets eliminated)
3 × 3 = 9
So you end up with
9x + 3y = 9
x - 3y = -2
(add)
10x = 7
So your answer is B. 10x = 7. I hope this helps!