Multily everything by 20 to get
5(x+4) - 4 (x-1) = 300 expand
5x + 20 - 4x + 4 = 300 combine like terms
x + 24 = 300 subtract 24 from both sides
x = 276
I see a minor error in ElectricPavlov's solution. I think this is simply a copying error.
After multiplying by the LCM of the denominator on both sides, all existing fractions disappear.
5(x+2)-4(x-1)=300
5x+10-4x+4=300
x+14=300
x=286
I like to call this error a "flow-through" error.
Don't worry! It happens to all of us!
Here is an example where I fell victim to the "flow-through" error: https://web2.0calc.com/questions/monic-quartic#r1.
The question asks for a fourth-degree polynomial with given roots, and, of course, I misread some of the roots.