Question

Bài 1: b)(x+3)^2-x(x-5)=10  
c)  (x-5)(x+5)-(x-4)^2=20
d) x/5+2x+1/6=2(2x-2)/3

Answer 1

b: \(\left(x+3\right)^2-x\left(x-5\right)=10\)

=>\(x^2+6x+9-x^2+5x=10\)

=>11x=1

=>\(x=\dfrac{1}{11}\)

c: \(\left(x-5\right)\left(x+5\right)-\left(x-4\right)^2=20\)

=>\(x^2-25-\left(x^2-8x+16\right)=20\)

=>\(x^2-25-x^2+8x-16=20\)

=>8x-41=20

=>8x=61

=>x=61/8

d: \(\dfrac{x}{5}+\dfrac{2x+1}{6}=\dfrac{2\left(2x-2\right)}{3}\)

=>\(\dfrac{6x+5\left(2x+1\right)}{30}=\dfrac{20\left(2x-2\right)}{30}\)

=>6x+10x+5=40x-40

=>40x-40=16x+5

=>24x=45

=>\(x=\dfrac{45}{24}=\dfrac{15}{8}\)