4x +7 =18, then what is the value of 12x +21?
I don't know the value of x.
4x +7 =18
4x = 18 = 7
4x = 11
x = 11/4
x = 2.75
To find the value of 12x + 21, we first need to find the value of x in the given equation 4x + 7 = 18.
Step 1: Subtract 7 from both sides of the equation.
4x + 7 - 7 = 18 - 7
4x = 11
Step 2: Divide both sides of the equation by 4.
4x/4 = 11/4
x = 11/4
Now that we have the value of x, we can substitute it into the expression 12x + 21.
12(11/4) + 21 = 132/4 + 21 = 33 + 21 = 54
Therefore, the value of 12x + 21 is 54.