102, first you subtract 1 from 4 so thats 3 and then you add the 32 and 2 so now all you have to do is multiply the results of 4-1 and 32+2
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)
51/5 is equivalent to 10 and 1/5.
Since the height is different on both ends, we can assume that the wall is a trapezoid. Knowing that, we can replace the measures we know in the formula and our onky variable is the length of the wall - we only need to isolate it.
A= ((b+B)h)/2
26.4=((2+2.4)h)/2
52.8=4.4h
h=12