Toán c) (x – 2) mũ2 – (x + 5)(x – 5) = 10 d) 3(x – 0,1) – 0,2(x – 16,5) = 1 26/07/2021 By Brielle c) (x – 2) mũ2 – (x + 5)(x – 5) = 10 d) 3(x – 0,1) – 0,2(x – 16,5) = 1
\(\text{~~Phuong~~}\\c.(x-2)^2-(x+5)(x-5)=10\\\to x^2-4x+4-x^2+25=10\\\to -4x+29=10\\\to -4x=-19\\\to x=\dfrac{19}{4}\\\text{Vậy phuong trình có nghiệm x=} { \dfrac{19}{4} }\\d. 3(x-0,1)-0,2(x-16,5)=1\\\to 3x-0,3-0,2x+3,3=1\\\to 2,8x+3=1\\\to 2,8x=-2\\\to x=-\dfrac{5}{7}\\\text{Vậy phuong trình có nghiệm x=}-\dfrac{5}{7}\) Trả lời
`c) (x – 2)^2 – (x + 5)(x – 5) = 10` `⇔x^2-4x+4-(x^2-25)=10` `⇔x^2-4x+4-x^2+25=10` `⇔ -4x =10-25-4` `⇔ -4x =-19` `⇔x=19/4` Vậy `S={19/4}` `d) 3(x – 0,1) – 0,2(x – 16,5) = 1` `⇔10[3(x – 0,1) – 0,2(x – 16,5) ]= 10` `⇔30x-3-2x+33=10` `⇔30x-2x=10-33+3` `⇔28x=-20` `⇔x=-5/7` Vậy `S={-5/7}` Trả lời
\(\text{~~Phuong~~}\\c.(x-2)^2-(x+5)(x-5)=10\\\to x^2-4x+4-x^2+25=10\\\to -4x+29=10\\\to -4x=-19\\\to x=\dfrac{19}{4}\\\text{Vậy phuong trình có nghiệm x=} { \dfrac{19}{4} }\\d. 3(x-0,1)-0,2(x-16,5)=1\\\to 3x-0,3-0,2x+3,3=1\\\to 2,8x+3=1\\\to 2,8x=-2\\\to x=-\dfrac{5}{7}\\\text{Vậy phuong trình có nghiệm x=}-\dfrac{5}{7}\)
`c) (x – 2)^2 – (x + 5)(x – 5) = 10`
`⇔x^2-4x+4-(x^2-25)=10`
`⇔x^2-4x+4-x^2+25=10`
`⇔ -4x =10-25-4`
`⇔ -4x =-19`
`⇔x=19/4`
Vậy `S={19/4}`
`d) 3(x – 0,1) – 0,2(x – 16,5) = 1`
`⇔10[3(x – 0,1) – 0,2(x – 16,5) ]= 10`
`⇔30x-3-2x+33=10`
`⇔30x-2x=10-33+3`
`⇔28x=-20`
`⇔x=-5/7`
Vậy `S={-5/7}`