P = 5xyz + 2xy- 3×2 – 11
Q = 15 – 5×2 + 5xyz + 2xy
a. Tính P + Q
b. Tính P – Q
P = 5xyz + 2xy- 3×2 – 11 Q = 15 – 5×2 + 5xyz + 2xy a. Tính P + Q b. Tính P – Q
By Quinn
By Quinn
P = 5xyz + 2xy- 3×2 – 11
Q = 15 – 5×2 + 5xyz + 2xy
a. Tính P + Q
b. Tính P – Q
Đáp án:
Giải thích các bước giải:
$a)$
$P + Q = (5xyz + 2xy- 3x^2 – 11) + (15 – 5x^2 + 5xyz + 2xy)$
$= 5xyz + 2xy – 3x^2 – 11 + 15 – 5x^2 + 5xyz + 2xy$
$= (5xyz + 5xyz) +(-3x^2 – 5x^2 ) + (2xy + 2xy) + (-11 + 15)$
$= 10xyz – 8x^2 + 4xy + 4$
$b)$
$P – Q = (5xyz + 2xy – 3x^2 – 11) – (15 – 5x^2 + 5xyz + 2xy)$
$= 5xyz + 2xy – 3x^2 – 11 – 15 + 5x^2 – 5xyz – 2xy$
$= (5xyz – 5xyz) + (-3x^2 + 5x^2 ) + (2xy – 2xy) + (-11 – 15)$
$= 2x$=^2 – 26$
a, P+Q=(5xyz + 2xy- 3x² – 11)+(15 – 5x² + 5xyz + 2xy)
=5xyz + 2xy- 3x² – 11 + 15 – 5x² + 5xyz + 2xy
=(5xyz+5xyz)+(2xy+2xy)+(-3x²-5x²)+(-11+15)
=10xyz+2xy-8x²+4
b,P-Q=(5xyz + 2xy- 3x² – 11)-(15 – 5x² + 5xyz + 2xy)
=5xyz + 2xy- 3x² – 11 – 15 + 5x² – 5xyz – 2xy
=(5xyz-5xyz)+(2xy-2xy)+(-3x²+5x²)+(-11-15)
=2x²-26