若33x+1=81,则x=______,若642×83×2x=42x,则x2=______,若x-3y=4,则2x÷8y
来源:学生作业帮 编辑:搜搜考试网作业帮 分类:数学作业 时间:2024/08/06 07:06:23
若33x+1=81,则x=______,若642×83×2x=42x,则x2=______,若x-3y=4,则2x÷8y=______.
∵81=34,
∴3x+1=4,
解得x=1;
∵642×83×2x=(26)2×(23)3×2x=212×29×2x=221+x,
42x=[(22)2]x=24x,
∴21+x=4x,
解得x=7,
∴x2=72=49;
2x÷8y=2x÷(23)y=2x÷23y=2x-3y,
∵x-3y=4,
∴2x÷8y=24=16.
故答案为:1;49;16.
再问: - -soka
∴3x+1=4,
解得x=1;
∵642×83×2x=(26)2×(23)3×2x=212×29×2x=221+x,
42x=[(22)2]x=24x,
∴21+x=4x,
解得x=7,
∴x2=72=49;
2x÷8y=2x÷(23)y=2x÷23y=2x-3y,
∵x-3y=4,
∴2x÷8y=24=16.
故答案为:1;49;16.
再问: - -soka
若33x+1=81,则x=______,若642×83×2x=42x,则x2=______,若x-3y=4,则2x÷8y
若3x-4y=0,则x/y=______,(x-y)/y=______,(3x+2y)/(2x+3y)=_____.
若2x+3y-1=y-x-8=x+6,则2x-y=______.
若x+3y=3x+2y=7,则x=______,y=______.
若|x-y+2|与(x+y-1)2互为相反数,则x=______,y=______.
若实数x、y满足x2+y2-2x+4y=0,则x-3y的最大值是______.
若|3x-y-7|+(5x+2y-8)2=0,则x-y=______.
若x2-4x+y2+6y+13=0,则x=______,y=______.
若实数x,y满足3x2+2y2=6x,则x2+y2的最大值为______.
实数x,y满足x≥y≥1和2x2-xy-5x+y+4=0,则x+y=______.
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
若2x-3y=5,则6-4x+6y=______.