Answer:
Given the system of equation:
......[1]
......[2]
we can rewrite equation [2] as;
......[3]
Substitute equation [3] into [1] to eliminate x, and solve for y;

Using distributive property: 

Combine like terms;
16 - 8y = -4
Add 4 to both sides we have;
20 - 8y = 0
Add 8y to both sides we have;
20 = 8y
Divide 8 to both sides we have;

Substitute the y-value in [3] we have;

x = 8 - 5 = 3
Therefore, the expression should be substituted into the first equation is,
and also the value of x = 3 and y = 2.5
Answer:
B
Step-by-step explanation:
Answer:


Step-by-step explanation:
because 8(8)=64 and 8 is the positive square root of 64.
because 17i(17i)=289i^2=-289(-1)=-289.


Answer:
25 square units
Step-by-step explanation:
square 1 = 100 units (perimeter)
therefore each side = 25 units
square 2 = 225 square units (area)
therefore each side = 15 units
The sequence gradually decreases by 10.
Therefore square 3 each side would be 5 units.
To find the Area = 5×5
= <u>25 square units.</u>