Solve:
So far, I applied the LCD method to this. My LCD is 4b which I multiplied to the equation to get 4(5-b) + 3b = 7(4) which equals 20-4b+3b=28. From that point I'm unsure if you do set it to zero or set it as -4b+3b = 28-20 but it doesn't say solve for b. Or if the LCD method is even applied at all.
It doesn't "say" to solve for b, but that's the only variable in the equation, so solve actually means, "solve for b."
You already have the variable (b) on the left side and the constants on the right, so COMBINE like-terms on each side and solve for b.
You can check after to make sure your solution is correct. In other words, the value for b satisfies or makes the equation TRUE.