17) (Log(5) 36 + Log(5) 2 - Log(5) 8) * Log(9) 1/25 = Log(5) (36*2/8) * (-2Log(9) 5) = -Log(5) 9 * 2/Log(5) 9 = -2
18)
<span>x+3y=4</span>
<span>x^2-xy=8</span>
<span>x+3y=4</span>
y=(-x+4)/3
x^2-xy=8
x^2-x*((-x+4)/3)=8
4/3x^2-4/3x-8=0
D=(-4/3)^2-4*4/3*(-8)=400/9
x1=(20/3-(-4/3))/(2*4/3)=3
x2=(-20/3-(-4/3))/(2*4/3)=-2
x+3y=4
3+3y=4
y1=1/3
(-2)+3y=4
y2=2
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А) (3m + n)(3m - n) = 9m² - n²
б) (x - 4y)(x + 4y) = x² - 16y²
в) (2x - m)² = 4x² - 4xm + m²
г) (2x)² - m² = 4x² - m²