解3元1次方程组:① {2X-Y+Z=-3 {X+3Y-2Z=13 {3X-2Y-Z=2 ② {2X+4Y+3Z=9 {3X-2Y+5Z=11 {5X-6Y+7Z=13 ③ {X+Y+Z+-2 {5X+4Y+Z=O {3X+Y-4Z=11 ④ {X+Y=3 {Y+Z=5 {Z+X=4 ⑤ 当 Y= AX的平方+BX+C 当 X=1时 Y=-4 当 X=3时 Y=-20 当 X=-1时 Y=-12 求A,B
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![解3元1次方程组:① {2X-Y+Z=-3 {X+3Y-2Z=13 {3X-2Y-Z=2 ② {2X+4Y+3Z=9 {3X-2Y+5Z=11 {5X-6Y+7Z=13 ③ {X+Y+Z+-2 {5X+4Y+Z=O {3X+Y-4Z=11 ④ {X+Y=3 {Y+Z=5 {Z+X=4 ⑤ 当 Y= AX的平方+BX+C 当 X=1时 Y=-4 当 X=3时 Y=-20 当 X=-1时 Y=-12 求A,B](/uploads/image/z/11542853-29-3.jpg?t=%E8%A7%A33%E5%85%831%E6%AC%A1%E6%96%B9%E7%A8%8B%E7%BB%84%EF%BC%9A%E2%91%A0+%7B2X-Y%2BZ%3D-3+%7BX%2B3Y-2Z%3D13+%7B3X-2Y-Z%3D2+%E2%91%A1+%7B2X%2B4Y%2B3Z%3D9+%7B3X-2Y%2B5Z%3D11+%7B5X-6Y%2B7Z%3D13+%E2%91%A2+%7BX%2BY%2BZ%2B-2+%7B5X%2B4Y%2BZ%3DO+%7B3X%2BY-4Z%3D11+%E2%91%A3+%7BX%2BY%3D3+%7BY%2BZ%3D5+%7BZ%2BX%3D4+%E2%91%A4+%E5%BD%93+Y%3D+AX%E7%9A%84%E5%B9%B3%E6%96%B9%2BBX%2BC+%E5%BD%93+X%3D1%E6%97%B6+Y%3D-4+%E5%BD%93+X%3D3%E6%97%B6+Y%3D-20+%E5%BD%93+X%3D-1%E6%97%B6+Y%3D-12+%E6%B1%82A%2CB)
解3元1次方程组:① {2X-Y+Z=-3 {X+3Y-2Z=13 {3X-2Y-Z=2 ② {2X+4Y+3Z=9 {3X-2Y+5Z=11 {5X-6Y+7Z=13 ③ {X+Y+Z+-2 {5X+4Y+Z=O {3X+Y-4Z=11 ④ {X+Y=3 {Y+Z=5 {Z+X=4 ⑤ 当 Y= AX的平方+BX+C 当 X=1时 Y=-4 当 X=3时 Y=-20 当 X=-1时 Y=-12 求A,B
解3元1次方程组:
①
{2X-Y+Z=-3
{X+3Y-2Z=13
{3X-2Y-Z=2
②
{2X+4Y+3Z=9
{3X-2Y+5Z=11
{5X-6Y+7Z=13
③
{X+Y+Z+-2
{5X+4Y+Z=O
{3X+Y-4Z=11
④
{X+Y=3
{Y+Z=5
{Z+X=4
⑤
当 Y= AX的平方+BX+C
当 X=1时 Y=-4
当 X=3时 Y=-20
当 X=-1时 Y=-12
求A,B,C的值
解3元1次方程组:① {2X-Y+Z=-3 {X+3Y-2Z=13 {3X-2Y-Z=2 ② {2X+4Y+3Z=9 {3X-2Y+5Z=11 {5X-6Y+7Z=13 ③ {X+Y+Z+-2 {5X+4Y+Z=O {3X+Y-4Z=11 ④ {X+Y=3 {Y+Z=5 {Z+X=4 ⑤ 当 Y= AX的平方+BX+C 当 X=1时 Y=-4 当 X=3时 Y=-20 当 X=-1时 Y=-12 求A,B
把三元变为二元如:
X+Y+A=15 (1)
X-Y=-2 (2)
X+A=8 (3)
(1)+(2)得2X+A=13(4)
(4)-(3)得X=5
把X=5代入(2)得Y=7
把X=5代入(3)得A=3