rút gon bthức
a) (2x+1) ² +(2x+3) ² – 2(2x+1) ×(2x+3)
b) (2x-3) ×(2x+3)-(x+5) ² -x(x-1) ×(x+2)
c) (24x ²y ³z ² -12x ³y ²z ³+ 36x ²y ²z ²) :(-6x ²y ²z ²)
rút gon bthức
a) (2x+1) ² +(2x+3) ² – 2(2x+1) ×(2x+3)
b) (2x-3) ×(2x+3)-(x+5) ² -x(x-1) ×(x+2)
c) (24x ²y ³z ² -12x ³y ²z ³+ 36x ²y ²z ²) :(-6x ²y ²z ²)
Giải thích các bước giải:
\(\begin{array}{l}
a){(2x + 1)^2} + {(2x + 3)^2} – 2(2x + 1)(2x + 3) = {(2x + 1 – 2x – 3)^2} = {( – 2)^2} = 4\\
b)(2x – 3)(2x + 3) – {(x + 5)^2} – x(x – 1)(x + 2) = 4{x^2} – 9 – {x^2} – 10x – 25 – {x^3} + {x^2} – 2x = – {x^3} + 4{x^2} – 12x – 9\\
c)(24{x^2}{y^3}{z^2} – 12{x^3}{y^2}{z^3} + 36{x^2}{y^2}{z^2}):( – 6{x^2}{y^2}{z^2})\\
= \frac{{12{x^2}{y^2}{z^2}(2y – xz + 3)}}{{ – 6{x^2}{y^2}{z^2}}} = – 2y + xz – 3
\end{array}\)