for these you need to rearrange the equations and do substitutions.
#3 = if x+y=5 then you know x = 5-y
now substitute that equation for x in the 2nd one so x + 2y = 8 becomes
5-y + 2y = 8 2y - y becomes 1y which becomes y then subtract 5 from each side to get y =3
now replace y with 3 in the first equation x = 5-3 so x = 2
so (2,3) is the answer
same type of work for #4
2x-y=6 ,S0 y = 2X+6
so now you have 4x+2(2x+6)=-4
that becomes 4x +4x+12 = -4
8x+8 = 1, x =1
y = 2(1)-6 = -4
so answer is (1,-4)
Perimeter of square is P = 4s.....s = length of 1 side
so ur function rule is : y = 4x
The correct answer should be C to this question
(√3n)-23=16
Put all of the numbers without a variable on the right side of the equation
(√3n)=39
Simplify
<span>1.732051n</span>=<span>39
</span>
Divide 39 by 1.732051
n=<span>22.516658
Round
n=22.5</span>
Assuming 0 and 100 are included in the possible choices:
There are

multiples of 7 between 0 and 100, so there is a

probability of choosing a multiple of 7.