## anonymous one year ago 1/7(B+35)3 linear equations

1. anonymous

@Leong

2. anonymous

@ganeshie8

3. anonymous

@LynFran

4. anonymous

@Leong

5. anonymous

@mathway

6. anonymous

@izuru

7. anonymous

@mathstudent55

8. anonymous

can you help me @RunawayGalaxy

9. anonymous

Well you're not being too clear in the question you're asking here, do you want to solve for B ?

10. anonymous

yes

11. mathstudent55

I don't understand what the problem is. There is no equal sign, so this is not an equation. what do you need to do?

12. anonymous

ohh so sorry =3

13. mathstudent55

Ok. Let me write it again.

14. anonymous

ok

15. mathstudent55

Solve for B: $$\large \dfrac{1}{7}(B + 35) = 3$$

16. mathstudent55

Is that the problem?

17. anonymous

yes

18. mathstudent55

Ok. You have a multiplication of 1/7 on the left side that we need to get rid of. To get rid of a multiplication, you multiply by its reciprocal. The reciprocal of 1/7 is 7, so we multiply both sides by 7. Can you do that and show what you get?

19. mathstudent55

$$\large 7 \times \dfrac{1}{7}(B + 35) = 7 \times 3$$ What do you get?

20. anonymous

7b and 245

21. mathstudent55

No. On the let side, what is 7 * 1/7? The whole idea of multiplying both sides by 7 is to get rid of 1/7 on the left side. What is 7 * 1/7?

22. anonymous

1

23. mathstudent55

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24. mathstudent55

Correct. That means on the left side, we only have now: $$\large B + 35$$ On the right side, what is 7 * 3?

25. anonymous

21

26. mathstudent55

Correct. That means now we have $$\large B + 35 = 21$$

27. mathstudent55

We want B alone, but we have B + 35 on the left side. Since plus 35 means add 35, we do the opposite to get rid of the +35. We subtract 35. We must do the same to both sides of an equation, so we subtract 35 from both sides of the equation. $$\large B + 35 - 35 = 21 - 35$$ What do you get?

28. anonymous

35-21=14 B=14

29. anonymous

thanks. :)

30. anonymous

-14

31. mathstudent55

Be careful. The left side is correct. B + 35 - 35 is simply B. On the right side, you have 21 - 35, not 35 - 21. The answer is not B = 14

32. anonymous

lol

33. mathstudent55

Oh, I see. You got it. The answer is B = -14

34. anonymous

Sorry I didn't help, stepped away from the computer

35. anonymous

its fine took an hour to get help :P

36. mathstudent55

Now we check the answer in the original equation to see if it is correct. We get B = -14 If we plugin -14 for B in the original equation, we must get a true statement. $$\dfrac{1}{7}(B + 35) = 3$$ $$\dfrac{1}{7}(-14 + 35) = 3$$ $$\dfrac{1}{7}(21) = 3$$ $$3 = 3$$ Since 3 = 3 is a true statement, our solution B = -14 is correct.