Answer:
x = -1, y = 2 and z = 1
Step-by-step explanation:
The given system of equations are :
2x - y + 3z= -1 ....(1)
x + 2y - 4z = -1 ......(2)
y – 2z = 0 .....(3)
Equation (3) can be written as :
y = 2z
Use y = 2z in equation (2)
x + 2(2z) - 4z = -1
x + 4z - 4z = -1
x = -1
Put the value of x in equation (1) :
-2 -y +3z = -1
-y+3z = 1 ....(4)
Adding equation (3) and (4)
y-2z+(-y+3z)=1
z = 1
Now put z = 1 in equation (4)
-y+3=1
-y = -2
y = 2
Hence, the values of x,y and z are -1, 2 and 1 respectively.
Step-by-step explanation:


= -1 × 729
= -729
So in total, there are 7 marbles, (3 black + 4 red = 7 total marbles) and we want to find out how much black marbles are able to come out. So it would be 3/7. :)
x
The answer would be 12x^3+ 2x + 4
Scale = 1cm:3km
Therefore area of lake = 81Km
1:3 = x:81
= 27:81
Therefore the area on map is 27cm
Must click thanks and mark brainliest