Question

Giai phương trình

a) (x+5)(x+2)= 3(4x-3)+ (x-5)²

b) 12-2(1-x)²= 4(x-2)- (x-3)(2x-5)

c)

Answer 1

a) (x+5)(x+2)= 3(4x-3)+ (x-5)²

\(\Leftrightarrow\) x²+2x+5x+10 = 12x-9+x²-10x+25

\(\Leftrightarrow\) 5x+10 = -9+25 ​

\(\Leftrightarrow\) 5(x+2) = 16

\(\Leftrightarrow\) x+2 = \(\dfrac{16}{5}\)

​\(\Leftrightarrow\)​ x = \(\dfrac{26}{5}\)

Answer 2

b) 12-2(1-x)² = 4(x-2)- (x-3)(2x-5)

\(\Leftrightarrow\) 12-2(1-2x+x²) = (4x-8) - (2x²-5x-3x+15)

\(\Leftrightarrow\) 12-2+4x-2x² = 4x-8-2x²+5x+3x-15

\(\Leftrightarrow\) 10 = 8x-23

\(\Leftrightarrow\) 33 = 8x

\(\Leftrightarrow\) x = \(\dfrac{33}{8}\)