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The second problem of mathematics in grade three
1、x+2÷x=3

x? +2 = 3 times

x? -3x+2=0

(x- 1)(x-2)=0

X= 1 or x=2.

2、x+6÷x=5

x? +6 = 5 times

x? -x+5=0

(x- 1)(x-5)=0

X= 1 or x=5.

3、x+ 12÷x=7

x? + 12=7x

x? -7x+ 12=0

(x-3)(x-4)=0

X=3 or x=4.

And: x+(n? +n)÷(x-3)=2n+4

x(x-3)+(n? +n)=(2n+4)(x-3)

x? -3x+n? +n=2nx+4x-6n- 12

x? -3x-2nx-4x+n? +n+6n+ 12=0

x? -(2n+7)x+n? +7n+ 12=0

x? -[(n+3)+(n+4)]x+(n+3)(n+4)=0

[x-(n+3)][x-(n+4)]=0

X=n+3 or x=n+4.