Answer:
a. it has no solution
b. you can only substitute by making either the 'x' or 'y' the subject of either of the two equations.
Step-by-step explanation:
3x - 9y = -13.............. eqn 1
x - 3y = -7................... eqn 2
from eqn 2
x - 3y = -7, substitute by making 'x' the subject
x = -7 + 3y.................. eqn 3
put eqn 3 into eqn 1
3x - 9y = -13
3( -7 + 3y) - 9y = -13
-21 + 9y - 9y = -13
9y - 9y = -13 + 21
0 = 8, which is not possible.
Copper: Nickel = 4:1
a) How much copper needed for 20 kg nickel
C:N = 4: 1
C:20 = 4:1
C/20 = 4/1 Cross Multiply
C*1 = 4*20
C = 80
80kg Copper would be needed.
b) How much Nickel would be needed for 20 kg of Copper
C:N = 4: 1
20:N = 4:1
20/N = 4/1 Cross Multiply
4*N = 1*20
4N = 20 Divide both sides by N.
N = 20/4 = 5
5kg Nickel would be needed.
Answer:
the missing number is 84
Step-by-step explanation:
Let the missing number be represented by N. Then we have ...
7*3 = N*3/(4*3)
Canceling common factors on the right, we have ...
7*3 = N/4
Multiplying by 4 gives ...
4*7*3 = N = 84
The missing number is 84.
Absolute value describes the distance from zero that a number is on the number line, without considering direction. The absolute value of a number is never negative. Take a look at some examples. The distance from 5 to 0 is 5 units.
