what is 4/5+x=3/7

Question

I need the answer for my algebra take home test. I need the answers because my grandma and my dad do not know how to do it. Please help. I am 13 and in 8th grade at Larkspur Middle School.

Answer 1

1st I do not do student take home tests.  This doesn't teach you anything.  I will do a similar problem so that you can do your problem in the same manner.

5/2+2x=3/5             Let us first get rid of those nasty fractions by multiplying every term by LCD

                               LCD = 2*5=10

10(5/2) + 10*2x  = 10(3/5)       Cancel before you multiply.  This is a good habit to get into especially later when they use larger numbers or even variables.

5*5  + 20x  = 2*3

25  + 20x  = 6            subtract 25 from both sides

-25              -25

20x  = - 19                     finally divide

x = -19/20                 finally check your answer

5/2  + 2(-19/20) = 3/5

5/2 -38/20  = 3/5                  find LCD on left

5*10/2*10  - 38/20  = 3/5

50/20 - 38/20   = 3/5

12/20  = 3/5            Reduce

12/4  over  20/4

= 3/5  = 3/5   so it checks

Answer 2

4/5+X=3/7

X=3/7-4/5  Cross over to other side to answer for x

X=3/7(35/35)- 4/5(35/35) Find common multiple of  7 and 5

X=5/35(3/1) - 7/35(4/1)  Simplify and multiply 35 to each side

X= 15/35 - 28/35 Subtract

X= -13/35  Answer

Check Answer:

4/5-13/35=3/7  Substitute answer for x

(35/35) 4/5-13/35(35/35) = 3/7   Multuply by common multiple of 5 and 35

7/35(4/1) - 13/35(1/1) = 3/7  simplify and Multiply

28/35 - 13/35= 3/7  subtract

15/35= 3/7  Simpllify

3/7= 3/7   Answer is Correct.