Respuesta :
Answer:
- c = 3.09375
Step-by-step explanation:
Standard for of quadratic equation:
- ax² + bx + c = 0
We have
- 2x² - 5x + c = 0
Sum of the roots
- x₁ + x₂ = - b/a = -(-5)/2 = 2.5
Product of the roots
- x₁x₂ = c/a = c / 2
We have:
- x₁ - x₂ = 0.25
The square of the above is:
- (x₁ - x₂)² = (x₁ + x₂)² - 4x₁x₂
Substitute known values and solve for c:
- 0.25² = (2.5)² - 4(c/2)
- 2c = 6.25 - 0.0625
- 2c = 6.1875
- c = 3.09375
Answer:
c = 3.09375
Step-by-step explanation:
Factored form of a quadratic equation
[tex]y=a(x-r_1)(x-r_2)[/tex]
where:
- a is the leading coefficient
- [tex]r_1[/tex] and [tex]r_2[/tex] are the roots
Given quadratic:
[tex]2x^2-5x+c=0[/tex]
Therefore, the leading coefficient is:
[tex]\implies a=2[/tex]
Substitute the value of a into the formula:
[tex]\implies y=2(x-r_1)(x-r_2)[/tex]
Expand:
[tex]\implies y=2x^2-(2r_2+2r_1)x+2r_1r_2[/tex]
Compare the coefficients of x:
[tex]\implies -(2r_2+2r_1)=-5[/tex]
[tex]\implies 2r_2+2r_1=5[/tex]
[tex]\implies r_2+r_1=2.5[/tex]
If the difference between the roots is 0.25 then:
[tex]\implies r_2-r_1=0.25[/tex]
Add the two root equations to eliminate r₁:
[tex]\implies 2r_2=2.75[/tex]
[tex]\implies r_2=1.375[/tex]
Substitute the found value of r₂ into one of the root equations and solve for r₁:
[tex]\implies 1.375-r_1=0.25[/tex]
[tex]\implies r_1=1.375-0.25[/tex]
[tex]\implies r_1=1.125[/tex]
As c = 2r₁r₂ then:
[tex]\implies c=2(1.125)(1.375)[/tex]
[tex]\implies c=3.09375[/tex]
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