Question

What is 3/4 = w + 2/5

Answer 1

Convert all fractions to have the same denominator. 

To convert, we must find the least common multiple of the two denominators of the fractions:

Multiples of 4: {4,8,12,16,20}
Multiples of 5: {5,10,15,20}

The least common multiple of 4 and 5 is 20. 

Multiply the fractions by a number that will result in the denominator being 20:

$\frac{3}{4} * \frac{5}{5} = \frac{15}{20}$

$\frac{2}{5} * \frac{4}{4} = \frac{8}{20}$

The equation should now look like this:

$\frac{15}{20} = w + \frac{8}{20}$

Subtract both sides by 8/20 to get w by itself:

$\frac{15}{20} - \frac{8}{20} = \frac{7}{20}$

$w = \frac{7}{20}$

The value of w is 7/20.

Answer 2

First, you subtract 2/5 from 3/4 
To do this you must make them have a common denominator.
This is simple just multiply the top and bottom by the other factors denominator.

$\frac{3*5}{4*5}$ = $\frac{15}{20}$ 
$\frac{2*4}{5*4}$ = $\frac{8}{20}$
Now just subtract 15-8 and get $\frac{7}{20}$
which cannot simplify so w=$\frac{7}{20}$