( 3х^2 - 6х^2 ) / 3х^2 = ( - 3х^2 ) /3х^2 = ( - 1 )
<em>1. </em><em>(11a-b)² +(9a+7b)(8a-13b) = </em><em>11²a²-b²+9a+7b·8a-13b = 121a²+9a8a-b²+7b-13b = 121a²+72a²-b²+7b-13b=193a²-7b²</em>
<em>2.</em><em> (18x+5y)(2x-4y)-(6x-3y)² = </em><em>18x+5y·2x-4y-6²x²+3²y2 = 18x+5y·2x-4y-36x²+9y² = 10y²</em>
<em>3. </em><em>4x(3x-2y)-(10y-0,4x)²</em><em> = 12x²-8xy-100y²+8xy-0.16x² = 11.84x²-100y²</em>
<em>4. </em><em>(15a+2b)²-(3a-7b)(3b-5a) </em><em>= 15²a+2²b²-3a-7b·3b-5a = 225a²+4b²-3a-7b·3b-5a = 225a²+4b²-8a-21b²</em>
1)x-3y=0⇒x=3y
9y+5y=126
14y=126
y=126:14=9
x=3*9=27
2)y-3x=0⇒y=3x
3x+15x=126
18x=126
x=126:18=7
y=3*7=21
Ответ (27;9) (7;21)
А+6х / а : ах+6х² / а² = а+6х / а * а² / х(а+6х) = а/х = -64/ -64 = 1
<u>1 </u> - <u>9x+7</u> = <u> </u><u>7 </u> - <u>9x+7</u> = <u>7-9x-7</u> = <u>-9x</u> = <u>-1</u><u>
</u>9x 63x 63x 63x 63x 63x 7<u>
</u>