2) 30,68
4) 14
Объяснение:
2) (3х+4)²–10х–(х–4)(4+х)=9х²+24х+16–10х–(х–4)(х+4)=
=9х²+14х+16–(х²–16)=9х²+14х+16–х²+16=8х²+14х+32=
=8×(–0,1)²+14×(–0,1)+32=8×0,01–1,4+32=0,08+30,6=
=30,68
4) (а+3)²+(а–3)(3+а)–2(а+2)(а–4)=
=а²+6а+9+(а–3)(а+3)–2(а²–4а+2а–8)=
=а²+6а+9+(а²–9)–2(а²–2а–8)=
=а²+6а+9+а²–9–2а²+4а+16= 10а+16
подставим значение а= –1/5
2) 30,68
4) 14
Объяснение:
2) (3х+4)²–10х–(х–4)(4+х)=9х²+24х+16–10х–(х–4)(х+4)=
=9х²+14х+16–(х²–16)=9х²+14х+16–х²+16=8х²+14х+32=
=8×(–0,1)²+14×(–0,1)+32=8×0,01–1,4+32=0,08+30,6=
=30,68
4) (а+3)²+(а–3)(3+а)–2(а+2)(а–4)=
=а²+6а+9+(а–3)(а+3)–2(а²–4а+2а–8)=
=а²+6а+9+(а²–9)–2(а²–2а–8)=
=а²+6а+9+а²–9–2а²+4а+16= 10а+16
подставим значение а= –1/5