Question

2{9x/10+12/10(120-x)} = 240​

Answer 1

Step-by-step explanation:

Question 2:

Decide which of the following are quadratic equations.

(1) x2 + 5x – 2 = 0

(2) y2 = 5y – 10

(3) y2+

1

y

=2

(4) x+

1

x

=-2

(5) (m + 2) (m – 5) = 0

(6) m3 + 3m2 – 2 = 3m3

ANSWER:

(1) x2 + 5x – 2 = 0

Only one variable x.

Maximum index = 2

So, it is a quadratic equation.

(2) y2 = 5y – 10

Only one variable y.

Maximum index = 2

So, it is a quadratic equation.

(3) y2+

1

y

=2

⇒y3+1=2y

Only one variable y.

Maximum index = 3

So, it is not a quadratic equation.

(4) x+

1

x

=-2

⇒x2+1=-2x

Only one variable x.

Maximum index = 2

So, it is a quadratic equation.

(5) (m + 2) (m – 5) = 0

⇒m2-3m-10=0

Only one variable m.

Maximum index = 2