Упр.343 ГДЗ Муравин 7 класс (Алгебра)

1) (a + 2)(b + k); 7) (a^2 — 7)(a + 4);
2) (y — 6)(x — p); 8) (c + 5c)(1 — 4c);
3) (a + x)(a — 1); 9) (16x^2 — 7x)(0,5x — 3);
4) (b — 2)(b — 3); 10) (b^3 — 0,8b)(5b — 2);
5) (2c + 7)(c — 4x); 11) (a — 2/5)(a^2 + 35);
6) (5p + k)(p + 8k); 12) (y — 6y)(5/6 y — 2/3).

1. $$\begin{aligned} (a+2)(b+k)&=ab+ak+2b+2k \end{aligned}$$
2. $$\begin{aligned} (y-6)(x-p)&=yx-py-6x+6p \end{aligned}$$
3. $$\begin{aligned} (a+x)(a-1)&=a^2-a+ax-x \end{aligned}$$
4. $$\begin{aligned} (b-2)(b-3)&=b^2-3b-2b+6\\ &=b^2-5b+6 \end{aligned}$$
5. $$\begin{aligned} (2c+7)(c-4x)&=2c^2-8cx+7c-28x \end{aligned}$$
6. $$\begin{aligned} (5p+k)(p+8k)&=5p^2+40pk+pk+8k^2\\ &=5p^2+41pk+8k^2 \end{aligned}$$
7. $$\begin{aligned} (a^2-7)(a+4)&=a^3+4a^2-7a-28 \end{aligned}$$
8. $$\begin{aligned} (c+5c)(1-4c)&=6c(1-4c)\\ &=6c-24c^2 \end{aligned}$$
9. $$\begin{aligned} (16x^2-7x)(0{,}5x-3)&=8x^3-48x^2-3{,}5x^2+21x\\ &=8x^3-51{,}5x^2+21x \end{aligned}$$
10. $$\begin{aligned} (b^3-0{,}8b)(5b-2)&=5b^4-2b^3-4b^2+1{,}6b \end{aligned}$$
11. $$\begin{aligned} \left(a-\frac25\right)(a^2+35)&=a^3-\frac25a^2+35a-14 \end{aligned}$$
12. $$\begin{aligned} (y-6y)\left(\frac56y-\frac23\right)&=-5y\left(\frac56y-\frac23\right)\\ &=-\frac{25}{6}y^2+\frac{10}{3}y \end{aligned}$$

Ответ

1) $$ab+ak+2b+2k$$;
2) $$xy-py-6x+6p$$;
3) $$a^2-a+ax-x$$;
4) $$b^2-5b+6$$;
5) $$2c^2-8cx+7c-28x$$;
6) $$5p^2+41pk+8k^2$$;
7) $$a^3+4a^2-7a-28$$;
8) $$6c-24c^2$$;
9) $$8x^3-51{,}5x^2+21x$$;
10) $$5b^4-2b^3-4b^2+1{,}6b$$;
11) $$a^3-\frac25a^2+35a-14$$;
12) $$-\frac{25}{6}y^2+\frac{10}{3}y$$.