Question

Solve the equation.

-9/15y+3/21=5/15y-14/21

What is the solution?

a. y=68/315

b. y=31/105

c. y=85/98

d. y=85/25

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Answer 1

-9/15y+3/21=5/15y-14/21

Move 5/15y to the other side. Sign changes from +5/15y to -5/15y

-9/15y-5/15y+3/21=5/15y-5/15y-14/21

-14/15y+3/21=-14/21

Move 3/21 to the other side. Sign changes from +3/21 to -3/21.

-14/15y+3/21-3/21=-14/21-3/21

-14/15y=-14/21-3/21

-14/21-3/21=-17/21

-14/15y=-17/21

Multiply both sides by -15/14

-14/15y(-15/14)

Cross out 15 and 15, divide by 15 then becomes 1

Cross out 14 and 14, divide by 14 then becomes 1

1*1*y=y

-17/21*-15/14

Cross out 15 and 21 , divide by 3. 15/3=2, 21/3=7

17/7*5/14=85/98

Answer: c. y=85/98