Question

1/2s=4s-21 please show steps

Answer 1

Answer:

s = 6

Step-by-step explanation:

Goal is to isolate the variable (s)

1/2s = 4s - 21

Subtract 4s from both sides - this cancels out the 4s on the right side and moves it to the left side

1/2s - 4s = -21

To add or subtract fractions, they must have a common denominator

Convert 4s to a fraction over 2

1/2s - 8/2s = -21

Subtract the numerators and keep the denominators

-7/2s = -21

Remember the goal is to isolate the variable

In order to get rid of the -7/2, we multiply by its reciprocal (which is -2/7)

What we do to one side, we must do to the other (this means multiply by -2/7 on both sides

-7/2s × -2/7 = -21 × -2/7

s = -21 × -2/7

Negative × negative = positive

s = 42/7

Divide 42 by 7

s = 6