9) 2x^2-3x-15-5 10) x^2+2x-1=2 11) 2k^2+9k=-7 12) 5r^2=80

Question

Answer 1

9) To solve the equation

, we first simplify the equation by combining like terms:

Next, we can factor the quadratic equation:

Setting each factor equal to zero gives us the solutions:

or

Solving for

, we get:

or

Therefore, the solutions to the equation

are

and

.10) To solve the equation

, we first move all terms to one side of the equation:

Next, we can factor the quadratic equation:

Setting each factor equal to zero gives us the solutions:

or

Solving for

, we get:

or

Therefore, the solutions to the equation

are

and

.11) To solve the equation

, we first move all terms to one side of the equation:

Next, we can use the quadratic formula to solve for

:

Plugging in the values

,

, and

, we get:

Therefore, the solutions to the equation

are

and

.12) To solve the equation

, we first divide both sides by 5:

Next, we take the square root of both sides:

Therefore, the solutions to the equation

are

and

.

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