3х-4ч-ч=-2/5+3/7+4
х=-2 *1/70
Искомое число это 54<span>Так как 5+4=9 5*5+4*4=41 и 54-9=45</span>
(6+3b)(8a-6b) = 48a-36b+24ab-18b²= 24a(2+b)-18b(2+b)=(24a-18b)(2+b)
(-5x+7y)(8x+9) = -40x²-45x+56xy+63y = -5x(8x+9)+7y(8x+9) = (7y-5x)(8x+9)
(-2x-4y)(7x-9) = -14x²+18x-28xy+36y =2x(7x+9)-4y(7x+9) = (2x-4y)(7x+9)
(-7a+8b)(3a-7b)= -21a²+49ab+24ab-56b²=-21a²+25ab-56b²
(-7m-1)(-2n-2)= 14mn+14m+2n+2=14m(n+1)+2(n+1) = (14m+2)(n+1)