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Find discrimant of 3x^2-9x+20 |
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Answer» A quadratic equation is written in the form ax2+bx+c=0 Always change to this form firstThe discriminant is Δ=b2−4ac The solutions to an equation are called the \'roots\' and are referred to as αandβ The value of Δ tells us about the nature of the roots.If Δ>0⇒ the roots are real and unequal (2 distinct roots)If Δ>0 and a prefect square⇒ the roots are real, unequal and ................................................... rationalIf Δ=0⇒ the roots are real and equal (1 root)If Δ<0⇒ the roots are imaginary and unequalNote that if a or b are irrational, the roots will be irrational.−3x2+9x=4 ⇒3x2−9x+4=0 Δ=b2−4ac Δ=(−9)2−4(3)(4)=33 33>0 and is not a perfect squareTherefore, there are two roots which will be real and unequal. -159 by b² - 4ac |
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