Rut gon bieu thuc ( 2x like )
a)28^15 . 3^17
_____________
84^16
b) 3^10 + 6^2
________________
5.3^8 + 20
Rut gon bieu thuc ( 2x like )
a)28^15 . 3^17
_____________
84^16
b) 3^10 + 6^2
________________
5.3^8 + 20
Rut gon bieu thuc ( 2x like )
a)28^15 . 3^17
_____________
84^16
b) 3^10 + 6^2
________________
5.3^8 + 20
rut gon bieu thuc 3^6*45^4-3^10*15^3/27^4*25^3+45^6
1 rut gon bieu thuc ; A=5Ix+1I-3.[4-2x]
rut gon bieu thuc (5√3+3√5)÷15
rut gon bieu thuc (2x+3) mũ 2 +(2x+5) mũ 2
Lời giải:
$(2x+3)^2+(2x+5)^2=4x^2+12x+9+4x^2+20x+25$
$=8x^2+32x+34$
Rut gon cacc bieu thuc sau : ( 4x - 3 ).( x - 5 ) - 2x ( 2x- 11)
\(\left(4x-3\right).\left(x-5\right)-2x\left(2x-11\right)\)
=\(4x^2-20x-3x+15-\left(4x^2-22x\right)\)
\(=4x^2-20x-3x+15-4x^2+22x\)
\(=-x+15\)
rut gon bieu thuc (6x+7)(2x-3)-(4x+1)(3x-7/4)
x(x+4)-6(x-1)(x+1)+(2x-1)2 rut gon bieu thuc a tinh gia tri cua x de a co gia tri bang 3
\(A=x\left(x+4\right)-6\left(x-1\right)\left(x+1\right)+\left(2x-1\right)^2\)
\(A=x^2+4x-6\left(x^2-1\right)+\left(4x^2-4x+1\right)\)
\(A=x^2+4x-6x^2+6+4x^2-4x+1\)
\(A=-x^2+7\)
Để A có giá trị bằng 3 thì :
\(-x^2+7=3\)
\(-x^2=-4\)
\(x^2=4\)
\(x\in\left\{\pm2\right\}\)
Vậy..........