Question

CBSE
CLASS 8
SCIENCE LESSON 4 METALS AND NON METALS
Q.1. GALVANISATION IS
Q2.ANODISING IS
Q.3.WHICH OF THE FOLLOWING IS AN ALLOY OF IRON
Q.4.THE REDUCING ACTIVITY OF SODIUM IS REDUCED BY
Q.5.THE HARDEST KNOWN SUBSTANCE IS
Q.6.NON METALS WHICH FORM OXIDES ARE


​

Answer 1

Explanation:

EXPLANATION.

Equation ⇒ mx(6x + 10) + 25 = 0.

⇒ f(x) = mx(6x + 10) + 25.

⇒ 6mx² + 10mx + 25 = 0.

As we know that,

Discriminant = D.

D = b² - 4ac.

For real and equal roots,

D = 0  Or  b² - 4ac = 0.

⇒ (10m)² - 4(6m)(25) = 0.

⇒ 100m² - 600m = 0.

⇒ 100m(m - 6) = 0.

⇒ m = 0  or  m = 6.

                                                                                         

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) = imaginary, if D < 0.