0,4x(5x-4)+2x(0,8-x)=0
5x(2x-7)+2x(8-5x)=5
2(3x+4x^2)-8x(x+3
5x(2x+7)-3x(20x-5)=-100
6x^2-(2x+5)(3x-2)=7
4x^3+2x^2(5x-6x^3+x^4)
0,4x(5x-4)+2x(0,8-x)=0
5x(2x-7)+2x(8-5x)=5
2(3x+4x^2)-8x(x+3
5x(2x+7)-3x(20x-5)=-100
6x^2-(2x+5)(3x-2)=7
4x^3+2x^2(5x-6x^3+x^4)
Đáp án:
Giải thích các bước giải:
a. 0,4x(5x – 4) + 2x(0,8 – x) =0
⇔ 2x² – 1,6 + 1,6x – 2x² = 0
⇔ -1,6 + 1,6x = 0
⇔ -1,6(1 – x) = 0
⇔ 1 – x = 0
⇔ x = 1
b. 5x(2x – 7) + 2x(8 – 5x)=5
⇔ 10x² – 35x + 16x – 10x² = 5
⇔ -35x + 16x = 5
⇔ -19x = 5
⇔ x = -5/19
c. 2(3x+4x²) – 8x(x+3)
= 6x + 8x² – 8x² – 24x
= 6x -24x = -18x
d. 5x(2x+7)-3x(20x-5)=-100
e. 6x² – (2x+5)(3x-2) = 7
⇔ 6x² – 6x² +4x -15x +10 =7
⇔ -11x + 10 = 7
⇔ -11x = -3
⇔ x = 3/11
f. 4x² + 2x²(5x-6x²+x^4)
= 4x² + 10x³ – 12^4 +2^6
= 2x³(2+5x-6x²+x^4)
a)2x-16x^2+1,6x-2x^2=0
=>3,6x-18x^2=0
=>3,6x=18x^2
=>1=5x => x=1/5
b)10x^2-35x+16x-10x^2=5
=>19x=-5
=>x=-5/19
c)6x+8x^2-8x^2-24x=?(đề ko cho)
d)10x^2+35x-60x^2+15x=-100
=>50x-50x^2=-100
=>x-x^2=-2
=>x(x-1)=2
=>x=1