At 7 pm, the temperature was 66*F
Temp = 78 - 3x where x = number of hours
78 - 3(7-3)
78 - 12 = 66
<span>An algebraic expression is an expression constructed from a number of constants and variables utilizing algebraic operations. These algebraic operations are addition, subtraction, multiplication, division, and exponentiation. A constant is constant, so its value is unchanged. A variable changes based on the value provided. In the provided example, 2x-1, there are two constants, "2" and "1", and one variable "x." The algebraic operations utilized are multiplication and subtraction. In order to evaluate the value of the algebraic expression, the given value for the variable must be substituted for the variable x, and then the algebraic operations executed to obtain the answer.
For instance, if you were told that the value of x in this case was 2, then you would substitute the value 2 for x and perform the described operations. Remember to follow the order of operations when evaluating an algebraic expression!
2x-1 for x=2
2(2) - 1
4 - 1
3 is the answer.
Remember, even though the multiplication operation is not explicitly stated, it is implied that a constant attached to a variable (termed a coefficient) is multiplied with the value of the variable.</span>
X is your number
double it means 2 times x or 2x
add 4
2x+4
subtract my number
2x+4-x=x+4
subtract 3
x+4-3=x+1
the result is x+1 or your number plus 1
Setup 2 problems
2x - 7 < 15 and 2x - 7 > -15
2x < 22 2x > -8
x < 11 x > -4
Or you can write it -4 < x < 11
