Respuesta :

calculista
the complete question is
Four times the sum of a number and 15 is at least 120. Let x represent the number. Find all possible values for x.

let
x---------> represent the number

we know that
Four times the sum of a number and 15 is at least 120
This can be written mathematically as
 4(x + 15) >= 120
Solving for x 
 4(x + 15) >= 120 
4x + 60 >= 120 
4x >= 120 – 60 
4x >= 60 
x >= 60/4 
x >= 15 

x is greater than or equal to 15 
the solution is the interval [15,∞)
The complete question is:

Four times the sum of a number and 15 is atleast 120. Let x represent the number. Find all possible values for x.

Solution:
Four times the sum of a number and 15 is atleast 120
Four times means multiplied by 4.
Sum of a number and 15 can be translated to x + 15.

So, Four times the sum of a number and 15 can be written as 4(x + 15)

This result is atleast 120. Atleast 120 means equal to or greater than 120. So we can write the inequality as:

[tex]4(x+15) \geq 120 \\ \\ x + 15 \geq 30 \\ \\ x \geq 15[/tex]

Thus x can be equal to 15 or any number greater than 15. In interval notation this can be expressed as [15, ∞)
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