A school plans to demolish part of the old school buildings and rebuild them into new ones. It takes 80 meters per square meter to demolish the old school buildings and 700 yuan per square meter to build new school buildings. The total area of the old school buildings and new school buildings planned to demolish in the year is 7200 square meters. In the construction process, due to other reasons, the new school buildings only completed 80% of the plan, while the demolition of the old school buildings exceeded 10% of the original plan, Results the area of newly built and demolished school buildings is exactly equal to the original plan (1) Q: what are the areas of the school buildings originally planned to be demolished and newly built? (2) If the remaining part of the original reconstruction fund is used for Campus Greening (the cost of greening is 200 yuan per square meter), how many square meters can be afforested? 19: 30 before the answer and answer in place of additional points

A school plans to demolish part of the old school buildings and rebuild them into new ones. It takes 80 meters per square meter to demolish the old school buildings and 700 yuan per square meter to build new school buildings. The total area of the old school buildings and new school buildings planned to demolish in the year is 7200 square meters. In the construction process, due to other reasons, the new school buildings only completed 80% of the plan, while the demolition of the old school buildings exceeded 10% of the original plan, Results the area of newly built and demolished school buildings is exactly equal to the original plan (1) Q: what are the areas of the school buildings originally planned to be demolished and newly built? (2) If the remaining part of the original reconstruction fund is used for Campus Greening (the cost of greening is 200 yuan per square meter), how many square meters can be afforested? 19: 30 before the answer and answer in place of additional points

1. The newly built area is a and the reconstructed area is B
a+b=7200
0.8a+1.1b=7200
a=2400m2 b=4800m2
2 total savings: 0.2 * 700 * 2400-0.1 * 80 * 4800 = 297600
It can afforest 1488m2

On children's day, Xiaoqiang went shopping. Here is a dialogue between Xiaoqiang and his aunt in the store: Xiaoqiang: aunt! I have 10 yuan. I want to buy a box of biscuits and a bag of milk! If the price of each box of biscuits and each bag of milk is X Yuan and Y yuan respectively, (1) please find out the relationship between X and Y; (2) if the price of biscuits is an integer, ask for each box of biscuits The price of dry milk and each bag of milk

(1) We can get 0 ＜ x ＜ 10Y ＞ 0x + y ＞ 100.9x + y = 9.2 ∧ y = 9.2-0.9x, (2) substituting y = 9.2-0.9x into x + y ＞ 10 to get 0.1X ＞ 0.8, solving x ＞ 8, X ＜ 10, ∧ 8 ＜ x ＜ 10, X is an integer, ∧ x = 9, substituting x = 9 into y = 9.2-0.9x to get y = 9.2-0.9 × 9

Given the square of X + the square of Y - 2x + 2Y = - 2, find the value of the algebraic formula x to the power of 2008 + y to the power of 2009

The square of X + the square of Y - 2x + 2Y = - 2
(square of x-2x + 1) + (square of Y + 2Y + 1) = 0
(x-1)^2+(y+1)^2=0
x=1
y=-1
2008 power of X + 2009 power of y = 0

Three squares form a rectangle side by side. Draw three diagonal lines to form three angles. They are x, y, Z angles. Z angle is 45 degrees. How many degrees is the angle X + y + Z equal to?

Y Z is the same angle
X and y are internal angles
XYZ equal
x+y+z=135°