what is.7 of 39.4?????

39.4*.7=27.58

Having trouble solving equations with two variables..both unknown

To solve equations with two unknown variables, you typically need two equations. This allows you to eliminate one variable by substituting it in terms of the other variable. Let's consider an example:

Let's say we have the following system of equations:
Equation 1: 2x + 3y = 7
Equation 2: 4x - 2y = 10

To solve this system of equations, you can use a method called substitution or elimination. Let's use the substitution method:

1. Solve one equation for one variable in terms of the other variable. For example, in Equation 1, solve for x:
2x = 7 - 3y
Divide both sides by 2:
x = (7 - 3y) / 2

2. Substitute the expression for x in terms of y (from step 1) into the other equation. Let's substitute x into Equation 2:
4((7 - 3y) / 2) - 2y = 10

3. Simplify and solve for y:
Distribute 4 to both terms inside the parentheses:
(28 - 12y) / 2 - 2y = 10
Simplify further:
(28 - 12y - 4y) / 2 = 10
Combine like terms:
(28 - 16y) / 2 = 10
Multiply both sides by 2 to eliminate the fraction:
28 - 16y = 20
Subtract 28 from both sides:
-16y = 20 - 28
-16y = -8
Divide both sides by -16:
y = -8 / -16
y = 0.5

4. Substitute the value of y (from step 3) back into one of the original equations (Equation 1 in this case) to solve for x:
2x + 3(0.5) = 7
Simplify:
2x + 1.5 = 7
Subtract 1.5 from both sides:
2x = 7 - 1.5
2x = 5.5
Divide both sides by 2:
x = 5.5 / 2
x = 2.75

So the solution to the system of equations is x = 2.75 and y = 0.5.