Answer:
A
Step-by-step explanation:
That's the formula for the solution of a quadratic equation, like this:

The formula is:

In your case:

The only answer that has c = -2 is the first one, A.
If you move the 5 to the left-hand side, it becomes -5 and with the +3 gives a -2.
Question: Where is the y2? Please be more specific!
(1) The value of x is 25
(2) The measure of ∠CBD is 60°
Explanation:
(1) The given two angles are vertical angles. Since, vertical angles are equal, we can add the two angles to determine the value of x.
Thus, we have,

Subtracting 5x from both sides, we have
Adding 10 to both sides , we have,

Thus, the value of x is 25.
(2) It is given that the measure of ∠ABC = (x+7)° and ∠CBD = (2x+14)°
Since, these two angles are supplementary angles and supplementary angles add upto 90°
Thus, we have,

Simplifying, we get,



Thus, substituting the value of x in ∠CBD = (2x+14)° to determine its value.

Thus, the measure of ∠CBD is 60°
Answer:
y = 27.1
Step-by-step explanation:
We have the value of x:
x = 12
and we need to find the value of y in the expression:
y = x + 15.1
as we can see by the equation, the value of y depends on the value of x.
thus, we substitute x = 12 on the previous equation:
y = 12 + 15.1
y = 27.1
the value of y is 27.1