Answer:
13
Step-by-step explanation:
The solution to the given equation is x = ±7. The correct option is d. x = ±7
<h3>Solving quadratic equations </h3>
From the question, we are to determine the solution to the given equation
The given equation is
x²-49 = 0
NOTE: I assumed the variable is x
Solving the equation
x²-49 = 0
Writing in the form ax²= c
x² = 49
∴ x = ±√49
x = ±7
Hence, the solution to the given equation is x = ±7
Learn more on Solving quadratic equations here: brainly.com/question/24334139
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Let D be Daniel's present age, then we can represent Kevin's present age as 3D because Kevin is 3 times as old as Daniel.
We can write an expression for Daniel's age 4 years ago as D-4 and Kevin's age 4 years ago as 3D-4.
We are told that 4 years ago Kevin was 5 times as old as Daniel. We can write this information as:
Now let us solve our equation to find Daniel's present age.
Daniel's present age is 8 years. Now we will multiply 8 by 3 to get Kevin's present age as Kevin is 3 times old as Daniel.
Therefore, Kevin is 24 years old now.
Most of these problems are the commutative property:
Addition
a + b = b + a
Multiplication
a * b = b * a
and the associative property:
Addition
(a + b) + c = a + (b + c)
Multiplication
(a * b) * c = a * (b * c)
There's also the Identity property:
Addition \ Subtraction:
a + 0 = a \ a - 0 = a
Multiplication \ Division:
a * 1 = a \ a / 1 = a