Answer:
If the Upper equation is 1 and the lower is 8:
1
7
8
6
5
The mistake was when she multiplied the 2nd equation by 5, she forgot to also multiply that last number 10 by 5 as well.
correction :
5x + 3y - z = 15
-x + 2y + 3z = 10...multiply by 5
---------------------
5x + 3y - z = 15
-5x + 10y + 15z = 50 (result of multiplying by 5)
--------------------add
13y + 14z = 65
B, infinite solutions if x = x
Answer:
T
he two polygons have 8 sides and 5 sides.
Step-by-step explanation:
A purely algebraic solution seems as if it would be very messy. Use trial and error, along with the formula for the number of diagonals in a n-sided polygon.
number of diagonals in a polygon with n sides: n(n-3)/2
10 sides and 3 sides: 10(7)/2 + 3(0)/2 = 35+0 = 35 nope....
9 sides and 4 sides: 9(6)/2 + 4(1)/2 = 27+2 = 29 nope....
8 sides and 5 sides: 8(5)/2 + 5(2)/2 = 20+5 = 25 yep!
