Y equals -34. First, you multiply both sides of the equation by the number 2 ... [2* y/2 + 2*5= -2*12 ] 2 cancels out and now your left with [y+2*5=-2*12] which turns into [ y+10=-2*12] after you multiply 5*2. Which now turns into [y+10= -24] after you multiply -2*12.
Secondly, you subtract 10 from both sides of the equation! (y+10-10=-24-10) y is now isolated because +10-10 cancels out !
Lastly, you are are left with y= -24-10... once you calculate this you will get the answer -34 !
The astronomer has to choose 3 star images out of 8.This is a problem of combinations. This can be expressed as 8C3 i.e. combination of 8 objects taken 3 at a time.
This means, if 8 images are nearby the astronomer will have 56 choices <span>of the three stars.</span>
