Answer:
m=-4
Step-by-step explanation:
5m-10m=-10m+5m=-(10m-5m)=-5m=20
divide by 5 on both sides, -m=4
miltiply by -1 on both sides, m=-4
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.
18 - 7x = -20.5
Subtract 18 from each side:
-7x = -38.5
Divide both sides by -7:
x = -38.5 / -7
x = -5.5 = 5 1/2
The answer is D.
