Yes, since adding two like variables will always result in the same variable.(i.e. x+x=2x not x^2). Any expression with the highest variable being to the power of 1 (or just x) is ALWAYS a linear expression.
Answer: C) All real values of x such that 
In other words, x must be 0 or smaller.
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Explanation:
The reason why is because we must make the stuff under the square root to never be negative. We must make -2x be 0 or larger.
So,

As an example, if x = -2, then -2x = -2(-2) = 4 is positive. Applying the square root to a positive number is valid.
But if x = 5, then -2x = -2*5 = -10 is under the square root, which is not allowed.
The answer your looking for is A hope it helps ;)
8.25%=8 1/4
8.25% of a gallon is 1.32 cups
Step-by-step explanation:
1/3=33.3%
33.3÷4=8.25%
8.25/1 x 100/100 = 825/100
825+100=8 1/4
6a-11=13
add 11 to both sides cross out -11 with +11
13+11 =24
6a=24
divide 6 on both sides
a= 4