Well that's easy put the three in place of the "X" and add or what ever it says
A mathematical expression in its' most simplistic form, merely assigns a value to a variable. Don't confuse an expression with an equation. An equation requires a solution. An expression cannot be "solved". It only allows you to determine the value of a variable. This is the expression in words "x is equal to 3" (X is the variable which is equal to the constant number 3) This is the expression in numbers "x=3" The expression in words "y is equal to 6" (Y is the variable which is equal to the constant number 6) The expression in numbers is "y=6" I hope you understand now.
True
You cannot explicitly find the value of x without an equal sign, as an equation without an equals sign is an algebraic expression. However, we can turn your expression into an equation by adding in an equals sign, but setting the value to a variable. For example, 2x+5=y, or 5x2-4x=y. You can solve for x like that. The phrase "... there is no equal sign in the equation ..." is a meaningless description. Without an 'equal' sign, there is no equation.
1
It is 2x + 5. The value of this expression will depend on the value of x: each different value of x will give a different value for the expression.
2
4
This is wrong
Any number that can be expressed as a fraction is a rational number otherwise it is an irrational number.
6
The value of the denominator cannot be zero.
You can replace a variable with an equal value or expression. Just make sure the same variable always gets the same value or expression.
Since there is no expression given, there is no sensible answer.
When the number is 0.
It means that the number or expression on the left of the symbol is less that the value or expression to the right, or that they are equal.
When the numbers are negative
In mathematics, such expressions indicate that the value of the expression to the left of the equal sign has the same value as the expression to the right of the equal sign. In some cases, it can also be interpreted to mean that the expression on one side of the equal sign can be used in place of the expression on the other side of the equal sign (say in manipulating algebraic expressions). In computer languages, the equal sign is sometimes also used to indicate that the value of the expression to the right of the equal sign is to be transferred to the location indicated by the expression to the left of the equal sign. The expression to the left of the equal sign is usually a single variable that represents a memory location.