Animated Solution for Mathematics - Quadratic Equations: Find all real values of x which satisfy x2−3x+2>0 and x2−2x−4≤0
Visualized Solution
System of Inequalities
Given System:
1. x2−3x+2>0
2. x2−2x−4≤0
Goal: Find the intersection of both solution sets.
Analyzing the First Inequality
Inequality 1:x2−3x+2>0
We need to factorize this quadratic expression.
Find two numbers that multiply to 2 and add up to −3.
Factorizing x2−3x+2
The numbers are −1 and −2.
Factored form: (x−1)(x−2)>0
Critical points: x=1 and x=2.
Solution Set for Inequality 1
Since (x−1)(x−2)>0, the expression is positive outside the roots.
Solution: x∈(−∞,1)∪(2,∞)
Note: Strict inequality means 1 and 2 are not included (hollow circles).
Analyzing the Second Inequality
Inequality 2:x2−2x−4≤0
This quadratic does not factorize easily with integers.
We must use the quadratic formula: x=2a−b±b2−4ac
Applying the Quadratic Formula
For x2−2x−4=0:
a=1, b=−2, c=−4
Substitute into the formula:
x=2(1)−(−2)±(−2)2−4(1)(−4)
Calculating the Roots
Simplify the expression:
x=22±4+16
x=22±20
x=22±25=1±5
Solution Set for Inequality 2
Since x2−2x−4≤0, the expression is negative between the roots.
Solution: x∈[1−5,1+5]
Note: Non-strict inequality means roots are included (solid circles).
Finding the Intersection
We must find where both conditions are true simultaneously.
Look for the overlap between the blue rays and the green segment.
Overlap 1: Between 1−5 and 1.
Overlap 2: Between 2 and 1+5.
Final Solution
Left overlap: [1−5,1)
Right overlap: (2,1+5]
Final Answer:x∈[1−5,1)∪(2,1+5]
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The Sigma Insight: Solution of Quadratic Equations
Solution Diagram
Analyzing the First Suspect
We begin with the first quadratic inequality: x2−3x+2>0. This represents a parabola that opens upward since the coefficient of x2 is positive.
To find where the parabola rises above the x-axis, we factorize the expression. We seek two numbers that multiply to 2 and add to −3, which are −1 and −2.
This gives us the factored form:
(x−1)(x−2)>0
The roots of this equation are x=1 and x=2. Because the parabola opens upward, it remains above the x-axis outside of these roots.
Thus, our first solution set is:
x∈(−∞,1)∪(2,∞)
Analyzing the Second Suspect
Next, we address the second inequality: x2−2x−4≤0. Since this does not factorize cleanly, we apply the quadratic formula:
x=2a−b±b2−4ac
Substituting a=1, b=−2, and c=−4, we obtain:
x=2(1)2±(−2)2−4(1)(−4)=22±4+16=22±20=1±5
Because we require the region where the expression is less than or equal to zero, we are interested in the "valley" of the parabola, which lies between the roots.
Therefore, our second solution set is:
x∈[1−5,1+5]
The Grand Finale
Finding the Intersection
To solve the system, we must find the overlap between our two solution sets. We compare the intervals (−∞,1)∪(2,∞) and [1−5,1+5].
Note that 1−5≈−1.23 and 1+5≈3.23. By observing the number line, we identify the regions where both conditions are satisfied simultaneously.
The intersection of these two sets is:
x∈[1−5,1)∪(2,1+5]
You have successfully navigated the constraints and identified the precise range of values that satisfy both inequalities. Keep this analytical mindset, and no problem will ever be too complex for you.