x^2+mx-28=(x-7)(x+4)
Answers
EXPLANATION.
⇒ x² + mx - 28 = (x - 7)(x + 4).
As we know that,
Factorizes the equation into simple form, we get.
⇒ x² + mx - 28 = x² + 4x - 7x - 28.
⇒ x² + mx - 28 = x² - 3x - 28.
⇒ x² + mx - 28 - x² + 3x + 28 = 0.
⇒ mx + 3x = 0.
⇒ x(m + 3) = 0.
⇒ m + 3 = 0.
⇒ m = -3.
MORE INFORMATION.
Nature of the factors of the quadratic expression.
(1) = Real and different, if b² - 4ac > 0.
(2) = Rational and different, if b² - 4ac is a perfect square.
(3) = Real and equal, if b² - 4ac = 0.
(4) = If D < 0 Roots are imaginary and unequal or complex conjugate.
EXPLANATION.
⇒ x² + mx - 28 = (x - 7)(x + 4).
As we know that,
Factorizes the equation into simple form, we get.
⇒ x² + mx - 28 = x² + 4x - 7x - 28.
⇒ x² + mx - 28 = x² - 3x - 28.
⇒ x² + mx - 28 - x² + 3x + 28 = 0.
⇒ mx + 3x = 0.
⇒ x(m + 3) = 0.
⇒ m + 3 = 0.
⇒ m = -3.
MORE INFORMATION.
Nature of the factors of the quadratic expression.
(1) = Real and different, if b² - 4ac > 0.
(2) = Rational and different, if b² - 4ac is a perfect square.
(3) = Real and equal, if b² - 4ac = 0.
(4) = If D < 0 Roots are imaginary and unequal or complex conjugate.
Hope it helps.