4x - 7y = 320

To solve the equation 4x - 7y = 320, you can use a method called substitution or elimination.

Substitution Method:
1. Solve one of the equations for one variable in terms of the other variable. Let's solve for x:
4x - 7y = 320
4x = 7y + 320
x = (7y + 320)/4

2. Substitute the expression for x in the other equation:
Substitute x in another equation (if there is another equation), and solve for y.
Let's assume there is no other equation given.

3. Substitute the value of y back into the equation to find the value of x:
Substitute the value of y into any of the original equations and solve for x.

Elimination Method:
1. Multiply one or both of the equations by a suitable number(s) so that the coefficients of one of the variables will be equal or opposite.
In this case, we can multiply the first equation by 7 and the second equation by 4 to eliminate the variable x.

2. Add or subtract the equations to eliminate one of the variables.
(7)(4x - 7y) = (7)(320) --> 28x - 49y = 2240
(4)(3x + 8y) = (4)(480) --> 12x + 32y = 1920

Now, subtract the second equation from the first equation:
(28x - 49y) - (12x + 32y) = 2240 - 1920
16x - 81y = 320

3. Solve the resulting equation for one variable.
16x - 81y = 320

4. Substitute the value(s) obtained into either of the original equations to find the value(s) of the other variable(s).