Equations don't really have x intercepts, functions or curves do. They're also known as the zeros of the function. When we set a function equal to zero we get an equation to solve, and the zeros of the function become the solutions or roots of the equation.
If a quadratic equation only has one root, that's a repeated root corresponding to a discriminant of zero.
In this example our equation is something like , or expanded
The discriminant here is
Answer:
Using the Angle Addition Postulate, 20 + m∠DBC = 80. So, m∠DBC = 60° using the subtraction property of equality.
Step-by-step explanation:
If point D is the interior of angle ABC, then the angle addition postulate theory states that the sum of angle ABD and angle DBC is equals to angle ABC. The angle addition postulate is used to measure the resulting angle from two angles placed side by side.
From the attached image, ∠ABD and ∠DBC are placed side by side to form ∠ABC. Given that m∠ABD = 20° and m∠ABC = 80°
Hence, using angle addition postulate:
m∠ABD + m∠DBC = m∠ABC
20 + m∠DBC = 80
subtracting 20 from both sides (subtraction property of equality)
m∠DBC = 80 - 20
m∠DBC = 60°
