What is a given that : 3a/7 = -2/5   

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justaguide's profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

We have to find the value of a given that: 3a/7 = -2/5

3a/7 = -2/5

multiply both sides by (7/3)

=> (3/7)*(7/3)*a = (-2/5)(7/3)

=> a = (-2*7)/(5*3)

=> a = -14/15

The required value of a = -14/15

zumba96's profile pic

zumba96 | Student, Grade 11 | (Level 3) Valedictorian

Posted on

Since 3a/7 = -2/5 and you need to find a, what I did was 

First I moved the 7 to the other side to the variable would be left alone. 

`(3a)/7` (7)=-`(2/5)(7)`

``

Divide that by 3 and it becomes -.93333333333

If you turn it into a fraction it would become -14/15

` `

atyourservice's profile pic

atyourservice | Student, Grade 11 | (Level 3) Valedictorian

Posted on

3a/7 = -2/5

cross multiply

3a x 5 = 15a

7 x -2 = -14

15a = -14

divide by 15

a = -14 / 15

giorgiana1976's profile pic

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

We'll use the cross multiplying to determine the value of a: the products of means is equal to the product of extremes.

7*(-2) = 5*3a

-14 = 15*a

Now, w'ell use symmetrical property:

15a = -14

We'll isolate a to the left side, dividing both sides by 15:

a = -14/15.

Therefore, the requested value of the unknown a is a = -14/15.

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