Answer:
this is so easy
Step-by-step explanation:
<span>x^2 + 15x + 56.25 = 105.25
"Completing the square" is one of many different techniques for solving a quadratic equation. What you do is add a constant to both sides of the equation such that the lefthand side can be factored into the form a(x+d)^2. For instance, squaring (X+D) = X^2 + 2DX + D^2. Notice the 2DX term. That is the same term as the 15x term in the problem. So 2D = 15, D = 7.5. And D^2 = 7.5^2 = 56.25.
So we have
x^2 + 15x + 56.25 = 49 + 56.25
Which is
x^2 + 15x + 56.25 = 105.25
Which is the answer desired.
Now the rest of this is going beyond the answer. Namely, it's answering the question "Why does complementing the square help?"
Well, we know that the left hand side of the equation can now be written as
(x+7.5)^2 = 105.25
Now take the square root of each side
(x+7.5) = sqrt(105.25)
And let's use both the positive and negative square roots.
So
x+7.5 = 10.25914226
and
x+7.5 = -10.25914226
And let's find X.
x+7.5 = 10.25914226
x = 2.759142264
x+7.5 = -10.25914226
x = -17.75914226
So the roots for x^2 + 15x - 49 is 2.759142264, and -17.75914226</span>
Answer:
The answer is B.
Step-by-step explanation:
You would pay about $20 each hour
Hi! There are 5,280 feet in a mile. Therefore, you need to divide 10,000 feet by 5,280 (to see how many miles there are per every 5280 feet) and you get 1.89 miles per hour.
<em>Answer:</em>
a = 7 & a = −7
<em>Explanation:</em>
Rewrite the equation as
(x+a)(x−a)=x^2−49
Simplify (x+a)(x−a)
x^2−a^2=x^2−49
Move all terms not containing a to the right side of the equation.
−a^2=−49
Multiply each term in −a^2=−49 by −1
a^2=49
Take the square root of both sides of the equation to eliminate the exponent on the left side.
a=±√49
The complete solution is the result of both the positive and negative portions of the solution.
a=7,−7
