Answer:
the answer is 10
Step-by-step explanation:
2x^2-y turns into
2*3^2-8
\ /
2*9-8
\ /
18-8
\ /
10
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Step-by-step explanation:
We need to say that
is equivalent to what.
We know that, (3)² = 9
So,

We can write 
And 
So,

So,
is equivalent to
.
Hence, this is the required solution.
Twice a number decreased by 11 is -23
Let the number be x
So we get the equation
2x -11 = -23
Add 11 to both sides
2x = -12
Divide both sides by 2
x = -6
So the number is -6
Negative 6