Given the square of x-2x-5 = 0, find the square of 10x-5x + 2013

Given the square of x-2x-5 = 0, find the square of 10x-5x + 2013

x²-2x-5＝0,
∴x²-2x=5
∴10x-5x²=-25
10x-5x²+2013=-25＋2013=1988

The square of 5x - 10x = - 5 is solved by factor method

The square of 5x - 10x = - 5
5x²-10x+5=0
5(x²-2x+1)=0
(x-1)²=0
∴x=1

Minus - 2x equals 6x2 + 3x-9, the algebraic formula is () a.6x-9 b.6x-9 C. - 6x-5x + 9 d.6x-9
Thank you very much

Minus - 2x equals 6x3 + 3x-9
(6x3+3X-9)+(-2x)=6x3+X-9
Choose D
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No matter what value x takes, there is (2x-a) (5x + 2) = 10x square - 6x + B. find the value of ah, B

（2x-a）（5x+2）=10x²-6x+b
10x²+（4-5a）x-2a=10x²-6x+b
Then: 4-5a = - 6 5A = 10 a = 2
b=-2a=-2*2=-4