Answer:
The answer is <u><em>7</em></u>!
Step-by-step explanation:
(x-4) (x) = 21, x^2 - 4x = 21, x^2 - 4x - 21 = 0, (x - 7) (x + 3) = 0, x = 7 and -3; x can't be negative so the answer is 7!
x = 7 and x - 4 (other side) = 3
You could complete the square to state the vertex.
You could use the quadratic equation to find the roots (which are complex).
Try an example that will require both.
y = x^2 + 2x + 5
Step One
Get the graph. That's included below.
Step Two
Provide the steps for completing the square.
Note: we should get (-1,4)
y= (x^2 +2x ) + 5
y = (x^2 +2x + 1) + 5 - 1
y = (x +1)^2 + 4
The vertex is at (-1,4)
Step Three
Find the roots. Use the quadratic equation. Note that the graph shows us that the equation never crosses or touches the x axis. The roots are complex.

a = 1
b = 2
c = 5




x = -1 +/- 2i
x1 = -1 + 2i
x2 = -1 - 2i And we are done.
Answer:
Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind.
Step-by-step explanation:
This is just an algebraic problem, the correct option is:
<em>"Myra should have multiplied 4.5 and 2.1 first."</em>
<h3>
How to evaluate an expression?</h3>
Here we want to evaluate the expression:
-31.7 + 4.5*x
in x = 2.1
This just means that we need to replace x by 2.1 in the given equation.
Now, what Myra does is:
-31.7 + 4.5*2.1 = -27.2*2.1
So she took the sum between -31.7 and 4.5 first, this is her mistake, you only would do that if the expression was:
(-31.7 + 4.5)*2.1
But in our expression:
-31.7 + 4.5*2.1
The first thing you need to solve is the product in the second term, so we get:
-31.7 + 4.5*2.1 = -31.7 + 9.45 = -22.25
If you want to learn more about algebra, you can read:
brainly.com/question/4344214