Question

помогите пожалуйста. № 8 и 9

Answer 1

▪▪▪8.

▪а)

$2 {x}^{2} - x - 1 = 2 \times {(0.5)}^{2} - 0.5 - 1 = 2 \times 0.25 - 0.5 - 1 = 0.5 - 0.5 - 1 = - 1$

▪б)

$9 {a}^{2} - 6 ab + {b}^{2} + 2a = {(3a - b)}^{2} + 2a = {(3 \times \frac{2}{3} - 2)}^{2} + 2 \times \frac{2}{3} =0 + \frac{4}{3} = 1 \frac{1}{3}$

▪в)

$18 {x}^{2} - 16l {x}^{4} - 3 {x}^{5} - 12 {l}^{5} {x}^{5} = 18 \times {1}^{2} - 16 \times ( - 1) \times {1}^{4} - 3 \times {1}^{5} - 12 \times {( - 1)}^{5} \times {1}^{5} = 18 + 16 - 3 + 12 = 43$

▪г)

$15 - 11s + 4 {s}^{3} = 15 - 11 \times 2 + 4 \times {2}^{3} = 15 - 22 + 32 = 25$

▪▪▪9.

▪а)

$7ab {a}^{2} - 3a \times {( - a}^{2} b) = 7 {a}^{3} b + 3 {a}^{3} b = 10 {a}^{3} b$

▪б)

$d \times 7cd \times {c}^{2} - 13 {c}^{3} {d}^{2} = 7{c}^{3} {d}^{2} - 13 {c}^{3} {d}^{2} = - 6 {c}^{3} {d}^{2}$

▪в)

$23 {(kt)}^{3} \div {k}^{2} + 17k {t}^{3} = 23k {t}^{3}+ 17k {t}^{3} = 40k {t}^{3}$

▪г)

$13 {j}^{2} w + 7 \times {(w {j}^{4}r) }^{2} \div (w {j}^{4} ) = 13 {j}^{2} w + 7w {j}^{4} {r}^{2}$

▪д)

$16b {n}^{2} b {n}^{3} - 7 {b}^{2} n {n}^{4} = 16 {b}^{2} {n}^{5} - 7{b}^{2} {n}^{5} = 9{b}^{2} {n}^{5}$

▪е)

$3 {g}^{4 } {x}^{7} + 5 {g}^{2} {x}^{5} {g}^{2} {x}^{2} - 4 {g}^{4} {x}^{7} = - ( {g}^{4} {x}^{7}) + 5 {g}^{4} {x}^{7} = 4 {g}^{4} {x}^{7}$

▪ж)

$- 4kl + 2k13l - lk = 21kl$

▪з)

$- 8 {p}^{4} {s}^{5} + p {p}^{2} s \times ( {s}^{2} ) ^{2} = - 8 {p}^{4} {s}^{5} + {p}^{3} {s}^{5}$