Упр.22.1 ГДЗ Мерзляк Поляков 8 класс (Алгебра)

1) x^2+8x+15; 2)-x^2+x+2; 3)-3a^2+8a+3;
4) 1/6 b^2-5/6 b+1; 5) 0,4x^2-2x+2,5; 6)-1,2m^2+2,6m-1.

1. $$x^2+8x+15=(x+5)(x+3).$$
2. $$-x^2+x+2=-(x^2-x-2)=-(x-2)(x+1)=(2-x)(x+1).$$
3. $$-3a^2+8a+3=-(3a^2-8a-3)=-(3a+1)(a-3)=(3a+1)(3-a).$$
4. $$\frac16 b^2-\frac56 b+1=\frac16(b^2-5b+6)=\frac16(b-2)(b-3).$$
5. $$0{,}4x^2-2x+2{,}5=0{,}4(x^2-5x+6)=0{,}4(x-2)(x-3).$$
6. $$-1{,}2m^2+2{,}6m-1=-1{,}2\left(m^2-\frac{13}{6}m+\frac56\right)=-1{,}2\left(m-\frac12\right)\left(m-\frac53\right).$$

Ответ

1) $$\left(x+5\right)\left(x+3\right);$$
2) $$\left(2-x\right)\left(x+1\right);$$
3) $$\left(3a+1\right)\left(3-a\right);$$
4) $$\frac16\left(b-2\right)\left(b-3\right);$$
5) $$0{,}4\left(x-2\right)\left(x-3\right);$$
6) $$-1{,}2\left(m-\frac12\right)\left(m-\frac53\right).$$