25x+20y=455
x+y=20
20x+20y=400
-25x-20y=-455
-5x=-55
x=11
11+y=20
y=9
Solved it as well, sorry if I wasn't supposed to
The answer is x = -3 / 2.
There are 1000 millimetres in a litre, so 1800 ml is 1.8 litres. 3-1.8 is 1.2.
1)
8² + 15² = 17²
64 + 225 = 289
This is true, so the triangle is a right triangle.
2)
4² + 12² = 13²
16 + 144 = 169
This is false, so the triangle is not a right triangle.
3)
20² + 21² = 27²
400 + 441 = 729
This is false, so the triangle is not a right triangle.
4)
28² + 45² = 53²
784 + 2,025 = 2,809
This is true, so the triangle is a right triangle.
He can write 2/3 of a page in 1/4 of an hour.
=> He can write 2/3 × 4 = 8/3 = 2 and 2/3 of a page in an hour
Answer: 2 and 2/3 of a page per hour
ok done. Thank to me :>