Respuesta :
System of equations y = x² + 7x + 4 has one real root with the line y = x -5.
What is the discriminant in the quadratic equation?
A quadratic equation is the polynomial equation of two degrees in one variable. The general form of a quadratic equation is ax² + bx + c = 0.
The quadratic equation formula for the solution of roots.
[tex]\rm (\alpha ,\beta ) = [ -b[/tex]±[tex]\rm \sqrt{b^{2} - 4ac} /2ac[/tex]]
The discriminant is the [tex]\rm \sqrt{b^{2} - 4ac}[/tex] part of the quadratic equation
If D is greater than zero then the roots are real and distinct.
If D is equal to zero then the roots are real and equal.
If D is less than zero then the roots are imaginary and unequal.
y = x² + 7x + 4
From First option, System of equations
y = x² + x – 4
y = x – 5
So, x - 5 = x² + x – 4
x² + x – 4 - x + 5 = 0
x² + 1 = 0
discriminant = b²- 4×a×c
= 0²- 4×1×1
-4 < 0, therefore the equation has no real roots.
From Second option, System of equations
y = x² + 2x – 1
y = x – 5
So, x - 5 = x² + 2x – 1
x² + 2x - 1 - x + 5 = 0
x² + x + 4 = 0
discriminant = b²- 4×a×c
= 1²-4×1×4
-15 < 0 therefore, the equation has no real roots.
From Third option, System of equations
y = x² + 6x + 9
y = x – 5
So, x - 5 = x² + 6x + 9
x² + 6x + 9 - x + 5 = 0
x² + 5x + 4 = 0
discriminant = b²- 4×a×c
= 5²-4×1×4
9 > 0 therefore, the equation has two different real roots.
From Fourth option, System of equations
y = x² + 7x + 4
y = x – 5
So. x - 5 = x² + 7x + 4
x² + 7x + 4 - x + 5 = 0
x² + 6x + 9 = 0
discriminant = b²- 4×a×c
= 6²-4×1×9 = 0
0 therefore, the equation has one real root.
Since, System of equations y = x² + 7x + 4 has one real root with the line y = x -5.
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