Interval notation question

[frctl]

If x = 5, then which interval contains this solution (it was derived from the original linear equation shown in the picture since I solved for x).

a. ]– ∞, – 7]
b. ] – 7, 1]
c. ] 1, 7] ∞[
d. ]7, ∞[

What I am not sure is the symbols of the interval signs or brackets, if the number appears before or after does it change the meaning? I am reading about their definitions on this website, and an explanation for '∞[' is not provided. According to my knowledge the answer appears to be d. ]7, ∞[ but I cannot confirm, does someone have any explanations that could help me understand more fully?

 

[skeeter]

If x = 5 …

[imath]\dfrac{7x}{3} = -4 + 3x[/imath]

[imath]x=5[/imath] ? ... try again.

 

[Dr.Peterson]

What I am not sure is the symbols of the interval signs or brackets, if the number appears before or after does it change the meaning? I am reading about their definitions on this website, and an explanation for '∞[' is not provided. According to my knowledge the answer appears to be d. ]7, ∞[ but I cannot confirm, does someone have any explanations that could help me understand more fully?

That site uses a different notation. Were you not taught the meaning of the notation used in this problem? Does the problem come from somewhere other than the course you are taking?

For something like your notation, see here and here.

 

[frctl]

Yes I made a mistake, I have arrived at the proper solution now thank you.