2017年GRE考试数学考点讲解10

　　Like real number, when multiplying a sum or difference of terms, the distributive property of multiplication allows us to distribute the multiplying term among the terms being added or subtracted.

　　Example:

　　3*(2x+y)=3*2x+3*y,

　　3a*(2x+y)=3a*2x+3a*y,

　　3x*(2x+y)=3x*2x+3x*y.

　　(3x+4)*(2x+y)=(3x+4)*2x+(3x+4)*y=3x*2x+4*2x+3x*y+4*y.

　　Remember:

　　Do not forget to multiply all the terms inside the parenthesis.

　　For division, the sum and difference in the numerator can be distributed:(x+y)/(2x+y)=x/(2x+y)+y/(2x+y).

　　For division, the sum and difference in the denominator cannot be distributed :(x+y)/(2x+y)≠(x+y)/2x+(x+y)/y.