If the question asks you to solve 4x+7=0, it is a problem asking you to solve to find the value of x. Essentially it is asking you what number can be multiplied by 4 and then added to 7 to equal 0? To solve this, you have to add, subtract, multiply, or divide the numbers so that the x is by itself. First you can subtract 7 from the left side of the equal sign and add it to the right side: 4x=-7. Then you divide 4x by 4 so that the left side will only have an x. Then you get x=(-7/4). If they are looking for a fraction, you are done with the equation. If they are looking for a decimal, simply use a calculator to divide -7 by 4 to get -1.75.