Put two cubes of the same size together. Guess how many faces there are now. If you put three cubes together?

Put two cubes of the same size together. Guess how many faces there are now. If you put three cubes together?

Two building blocks together, of course, are the same as one, with six sides,
Three together, there are three cases, there are six sides, seven sides and fourteen sides

Put two cubes of the same size together and guess how many faces there are now. If you put three cubes together?

Two cubes of the same size still have only six sides
The same is true for three cubes, which can only have six sides, but can also have seven sides based on different spelling

The surface of a large cube block is painted and sawed into 125 small blocks of the same size. The number of small blocks with different number of painted faces is calculated

Four cases:
There are 8 pieces on the corner and 3 sides are painted
3 * 12 on the edge = 36 pieces, two sides are painted
There are 54 pieces of 3 * 3 * 6 on the surface, and one side is painted
Center 3 * 3 * 3 = 27 pieces, no paint

-25X ^ 2 + 4 factorization (write steps)
Factorization: - 81 + A ^ 4 4 (x + 1) ^ 2-9 (3x + 2Y) ^ 2 - (2x + 3Y) ^ 2
x^2(a-1)+4(1-a)

-25x^2+4
=-(25x^2-4)
=-(5x+4)(5x-4)
-81+a^4
=a^4-81
=(a^2+9)(a^2-9)
=(a^2+9)(a+3)(a-3)
4(x+1)^2-9
=[2(x+1)+3]*[2(x+1)-3]
=(2x+5)(2x-1)
（3x+2y）^2-(2x+3y)^2
=[(3x+2y)+(2x+3y)]*[(3x+2y)-(2x+3y)]
=(5x+5y)(x-y)
=5(x+y)(x-y)
x^2(a-1)+4(1-a)
=x^2(a-1)-4(a-1)
=(a-1)(x^2-4)
=(a-1)(x+2)(x-2)

Factorization of x ^ 4-25x ^ 2 + 144

x⁴-25x²+144
=x⁴-24x²+144-x²
=(x²-12)²-x²
=(x²-12-x)(x²-12+x)
=(x-4)(x+3)(x+4)(x-3)

Decomposition factor: 25X & # 178; - 10x + 1

25x²-10x+1
=(5x)²-10x+1
=(5x-1)²
Do not understand welcome to ask

Factorization: 25X ^ 2-10x + 1 process

25x^2-10x+1
= (5x - 1)^2

Factorization of 25X ^ 2-30x + 9

The square of (5x-3)

Factorization: 25X ^ 2-100y ^ 2=——

25x^2-100y^2
=25(x^2-4y^2)
=25(x+2y)(x-2y)

Factorization of (m-n) (m-n + 2) - 8

(m-n)(m-n+2)-8
=(m-n)^2+2(m-n)-8
=((m-n)-2)((m-n))+4)
=(m-n-2)(m-n+4)