How do you solve 10≤2x≤x+9? The answer says it's 5≤x≤9 but i have no idea how it got there

Step-by-step explanation:

so why this kind of problem is so confusing is b/c it's 2 problems in one

if you were to expand this it look like this

10 ≤2x

and

2x ≤x+9

This is really saying.. that x has a range.. and that the 1st equations is the lower stop point,  and that the 2nd equations is the upper stop point

once it's taken apart.. I bet you can solve it pretty quickly.

5≤x

and

x ≤9

then just put it back together in that confusing .. yet handy way to write it,

5≤x≤9

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116