Answer:
The solution of the system is (5, 20).
Step-by-step explanation:
y = 4x and 3x + 2y = 55 are simultaneous equations. To find the unknowns, we have to solve these equations simultaneously.
The first can be rewritten as
4x – y = 0.
Therefore, we have:
4x – y = 0
3x + 2y = 55
Multiplying the first equation by 2 all through, we have
8x – 2y = 0.
So we can now combine the second equation with the first multiplied by 2.
8x – 2y = 0
3x + 2y = 55
Adding these equations we have:
11x = 55
Divide both sides by 11 and we have
x = 5
Substitute x = 5 in equation 1, we have
4(5) – y = 0
y = 20.
Therefore, x = 5 and y = 20.
The solution of the system is (5, 20).
Answer:
Work shown below!
Step-by-step explanation:
÷ 
= 
Answer:
8421
Step-by-step explanation:
8050 < abcd < 8500
We must have a = 8, so the number is 8bcd.
The value of a is 20 times the value of b, or a= 2b.
a = 8, so b = 4.
The value of b is 20 times the value of c, or b = 2c.
b = 4, so c = 2.
The value of c is 20 times the value of d, or c = 2d.
c = 2, so d = 1.
The secret number is 8421.
