21.
So to solve for the value of a variable in an equation, you would need to isolate x on one side. The first thing you have to do is multiply 2 and (x + 7) together, which can be rewritten as 2(x) + 2(7). After multiplying, your equation would be:
, or A.
22.
So the rule with multiplying exponents with the same base is to add the exponents together, and the rule with dividing exponents with the same base is to subtract the exponents. Your equation will be simplified as such:

Now the rule with converting negative exponents into fractions is
. In this case, 4^-2 would turn into
, or C, which is your final answer.
Answer:
15
Step-by-step explanation:
18-x=3
18-3=x
18-3=15
Answer:
Yes, this is a function
Step-by-step explanation:
You know this because it passes the vertical line test.
I hope this helps!
Answer:
see below. The solution is the doubly-shaded area.
Step-by-step explanation:
Each boundary line will be dashed, because the "or equal to" case is <em>not included</em>. Each shaded area will be above the corresponding boundary line because the comparison symbol is y > .... That is, only y-values greater than (above) those in the boundary line are part of the solution.
Of course, the boundary lines are graphed in the usual way. Each crosses the y-axis at the value of the constant in its equation. Each has a slope (rise/run) that is the value of the x-coefficient in the equation.
Answer:
x=-1, y=-3. (-1, -3).
Step-by-step explanation:
x+y=-4
3x-6y=15
---------------
x=-4-y
3(-4-y)-6y=15
-12-3y-6y=15
-12-9y=15
9y=-12-15
9y=-27
y=-27/9
y=-3
x+(-3)=-4
x-3=-4
x=-4+3
x=-1