(x+2)(x-5)-3x(1-2x)

To simplify the expression \((x+2)(x-5)-3x(1-2x)\), we will start by expanding both parts.

1. Expand \((x+2)(x-5)\): \[ (x+2)(x-5) = x^2 - 5x + 2x - 10 = x^2 - 3x - 10 \]

2. Expand \(-3x(1-2x)\): \[ -3x(1-2x) = -3x + 6x^2 = 6x^2 - 3x \]

3. Combine both expanded expressions: Now we substitute the expanded forms into the original expression: \[ x^2 - 3x - 10 + 6x^2 - 3x \]

4. Combine like terms: Combine the \(x^2\) terms and the \(x\) terms: \[ x^2 + 6x^2 - 3x - 3x - 10 = 7x^2 - 6x - 10 \]

Thus, the simplified expression is: \[ \boxed{7x^2 - 6x - 10} \]