## kiss69fist23 4 years ago 3. The diagonals of an isosceles trapezoid ,BD and AC, are labeled 5x and 3x + 40. Find the length of the diagonals. 3. The diagonals of an isosceles trapezoid ,BD and AC, are labeled 5x and 3x + 40. Find the length of the diagonals. @Mathematics

1. douce

5

2. kiss69fist23

3. kiss69fist23

how did you get 5

4. douce

becuz i am awesome

5. kiss69fist23

.........

6. kiss69fist23

can you please show me how to do it...?

7. douce

do not second guess me mortal

8. abdul_shabeer

I guess it to be 20

9. kiss69fist23

............ in any other case i would come back at you with disgust for mortals but i really have to get this done so can you please help me

10. douce

11. douce

i think my work here is done

12. kiss69fist23

13. Harkirat

diagonals of an isosceles trapezoid are equal in length

14. abdul_shabeer

As this is an isosceles trapezoid the line segments AD and BC are equal in length. So I suppose Diagonal to be equal and 5x = 3x+40. A linear equation in one variable.

15. Harkirat

5x and 3x + 40. so 5x = 3x + 40 5x - 3x = 40 x = 40/2 x = 20

16. Harkirat

so 5x = 5*20 = 100 3x + 40 = 3*20 + 40 = 60 + 40 = 100

17. abdul_shabeer

Your right, Harikat. I too wanted to type the same thing.

18. Harkirat

Ohh.... we were working on parallel tracks....☺

19. kiss69fist23

lozl the both of u r so cute haha

20. abdul_shabeer

In your profile : you said you hate math. It's such an excellent subject. It's my favourite

21. smartbrain

@Atsie this is a question I am stumbled on.

22. smartbrain

In this step 5x and 3x + 40. so 5x = 3x + 40 5x - 3x = 40 In this step why did they switch the equals sign and how do you know its minus not plus. @Atsie x = 40/2 x = 20

23. Atsie

@smartbrain I gotta go right now, I'll be back in an hour and then I'll answer ok?

24. smartbrain

I will probably be gone, but sure, that will help explain it. Ill see if somebody else can explain it meanwhile.

25. smartbrain

@AihberKhan can you possibly explain?

26. AihberKhan

@smartbrain Okay, so they are simply subtracting \(3x\) from both sides. Since they are subtracting, the positive \(3x\) becomes negative. You see? Also, they did not switch the equals sign they subtracted \(3x\) from both sides.

27. smartbrain

How did they conclude that the 3x is to be subtracted from both sides and not the 5x?

28. AihberKhan

If the \(5x\) is subtracted from both sides, then there will only be ONE side! Because if the \(5x\) was subtracted it would be \(=3x - 40 - 5x\) which simply can't happen.

29. smartbrain

I see, so you are trying to eliminate the x in the problem? Right?

30. AihberKhan

You are not trying to eliminate it. You are trying to isolate it. :) @smartbrain

31. smartbrain

Ok this answers my question. Thank you.

32. AihberKhan

No problem! :) Hope this helped! Have a great day! :) Also a medal would be much appreciated! Just click best response next to my answer. Thank You! Also, a fan will be much appreciated as well! Just hover over my avatar and click “Become a fan”. This will tell you whenever I am online so you can ask me for help in any of your other questions! If you see that I am online and need help with a question, just tag me in your question! @smartbrain