20. 3x2 + 2x + 5 is not a quadratic equation.*
True
False
21. If 2x + 3y = 0 and 4x - 3y = 0 then. x + y equals *
0
- 1
1
2
22. If ∑fi =15 , ∑fixi = 3p + 36 and mean of the distribution is 3 , then p is equal to *
2
3
4
5
23. A bag contains 4 red , 5 black and 3 yellow balls. A ball is taken out of the bag at random. The probability that the ball taken out is not of red colour is *
2/3
1/3
1/4
1/2
24. The common root of x2 – 7x + 10 = 0 and x2 – 10x + 16 = 0 is *
- 2
2
- 3
3
25. The difference between two numbers is 26 and one number is three times the other number. The numbers are *
39 , 13
30 , 10
40 , 14
30 , 40
Answers
Answer:
true because the answer is 13 x
Step-by-step explanation:
13x
Answer: 20 solution is false , 21) solution is 0(a) ,24) 2(b), 25) 39,13(a)..
Step-by-step explanation: 20) Because 3x2 + 2x + 5 had power 2 .
if any equation contains power 2 it is a quadratic equation.
21) Given equations are:
2x+3y=0.....(1)
4x−3y=0.....(2)
Now multiply (1) by (2) we get
4x+6y=0......(3)
Now subtracting (2) from (3), we get
⇒9y=0
⇒y=0
now substitute the y value in (3)
⇒4x+6(0)=0
⇒4x=0
⇒x=0
⇒x+y=0+0
⇒x+y=0
24)Let α be the common root.
∴α
2
−7α+10=0 ...(1)
and ∴α
2
−10α+16=0 ...(2)
Subtracting (2) from (1)
∴(α
2
−7α+10)−(α
2
−10α+16)=0−0
∴3α−6=0
∴α=2
25)Let the numbers be x and y
Given, x−y=26 --- (1)
Also, x=3y --- (2)
From equations (1) and (2), we get 3y−y=26⇒2y=26⇒y=13
So, x=3y=3×13=39
Numbers are 39,13
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