the square of a number is equal to the sum of 21 and 4 times the number. find the number
WHATS THE EQUATION (AM CONFUSED ?)
so its x=7
x= -3
x^2 = 21 + 4x
ok thanks
You're welcome.
To solve this problem, let's break it down step by step.
1. Assign a variable to represent the unknown number. Let's use "x" for this problem.
2. Translate the given information into an equation. The problem states that "the square of a number is equal to the sum of 21 and 4 times the number." In mathematical terms, this can be expressed as:
x^2 = 21 + 4x
3. Solve the equation to find the value of x. We can rearrange the equation by subtracting 4x from both sides:
x^2 - 4x = 21
4. Now, we have a quadratic equation. To solve it, we can set it equal to zero by subtracting 21 from both sides:
x^2 - 4x - 21 = 0
5. Factor the quadratic equation or use the quadratic formula to solve it. In this case, the equation can be factored as follows:
(x - 7)(x + 3) = 0
This results in two possible solutions: x = 7 or x = -3.
So, the two possible numbers that satisfy the given condition are 7 and -3.