Please someone help me on this one !! I need to pass this class!

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  x ≈ -0.5416

Step-by-step explanation:

As with any "solve for ..." problem, you essentially want to "undo" what has been done to the variable of interest. Here, if you were to evaluate the left-side expression (where the variable is) for some value of x, you would ...

You want to "undo" these operations in reverse order. That is, you work from the bottom of this list toward the top, using inverse operations along the way.

The inverse of addition is subtraction; the inverse of multiplication is division. The inverse of raising to a power is taking a logarithm.

undo add 5

undo multiply by 2

undo raise to a power (take logarithms)

undo add 7

undo multiply by 10

2500

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15