2) (x-3)×(4x+1)-(2x+1)^2
3) (3x-1)^2+(9×-1)×(2-x)
4) x (x-2)×(x+2)-(x+2)^2
(^ mũ )
Giúp vs cần gấp
2) (x-3)×(4x+1)-(2x+1)^2 3) (3x-1)^2+(9×-1)×(2-x) 4) x (x-2)×(x+2)-(x+2)^2 (^ mũ ) Giúp vs cần gấp
By Natalia
By Natalia
2) (x-3)×(4x+1)-(2x+1)^2
3) (3x-1)^2+(9×-1)×(2-x)
4) x (x-2)×(x+2)-(x+2)^2
(^ mũ )
Giúp vs cần gấp
2) $(x-3)(4x+1)-(2x+1)^2$
$=4x^2-11x-3-(4x^2+4x+1)$
$=-15x-4$
3) $(3x-1)^2+(9x-1)(2-x)$
$=9x^2-6x+1-9x^2+19x-2$
$=13x-1$
4) $x(x-2)(x+2)-(x+2)^2$
$=x(x^2-4)-(x^2+4x+4)$
$=x^3-4x-x^2-4x-4$
$=x^3-x^2-8x-4$
Đáp án:
1) 15x-4
2) 13x-1
3) x³+x²+4
Giải thích các bước giải:
1) (x-3)×(4x+1)-(2x+1)²
⇔4x²+x-12x-3-4x²-4x-1
=15x-4
2) (3x-1)²+(9x-1)×(2-x)
⇔9x²-6x+1+18x-9x²-2+x
=13x-1
3) x(x-2)×(x+2)-(x+2)²
⇔ x³-4x+x²-4x-4
= x³-x²-8x-4