Question

1)if the equations 2x +y=7 and x-y= 2 are solved simultaneously, then y =

(a)1 (b)-2 (c)-1 (d)+2 (e)3

2)Find the H.C.F of 12, 15 and 18.
(a) 2 (b)6 (c) 4 (d)5 (e)3

3)Express 100011two as a decimal number.
(a) 32 (b) 33 (c) 34 (d) 35 (e) 36​

Answer 1

one ×=y-7/2

two y=x-2

number 2 3

I didn't find any decimals

Answer 2

Explanation:

1) 2x + y =7 -------------(I)

x - y = 2 -----------(II)

2x + y = 7

x - y = 2 {Now add both the equations. 'y will be cancelled}

3x = 9

x = 9/3

x = 3

Plugin x = 3 in equation (I)

2*3 + y = 7

6+ y = 7

y = 7 - 6 = 1

Answer: a) y = 1

2) Prime factorize 12 , 15 and 18

12 = 2 * 2 * 3

15 = 3 * 5

18 = 2 * 3 * 3

HCF = 3

e) 3