Question

Questions in the comment !!

Answer 1

For the first one you can see that the sum is -1+6-2=3 from the last row.
From the second column you can check x: 1+6+x=3
So x=-4
Same way with y just from the diagonal: 1-1+y=3
So y=3
x-y=-4-3=-7

Answer 2

How about the second one?

Answer 3

Thinking...
Is that a right angle triangle? Looks so but than how is SQ=SR?

Answer 4

yup, right-angled triangle.

Answer 5

Wait I make a drawing for myself, 2 min

Answer 6

qs=qr
=> anger SQR = SRQ = 80 no there is not a right angle no enough information

Answer 7

This makes no sense to me sorry. If it is right angled than SQ cannot be equal to SR

Answer 8

if pqs is 90, then the triangle is right angle

Answer 9

another method is using sin or cosine rule... but there is no length information

Answer 10

ok. maybe the book itself got a problem. But anyway thanks and By the way there is answer at the back of the book but just not sure how to do the working... THANKS!

Answer 11

what is the ans??

Answer 12

10

Answer 13

when x=10