Question

运用完全平方公式计算,（3+x)^2= （y-7)^2= (7-y)^2= (-2x-3y)^2= (3-3分之1t)^

Answer 1

（3+x)^2=9+6x+x^2

（y-7)^2=y^2-14y+49

(7-y)^2=49-14y+y^2

(-2x-3y)^2=4x^2+12xy+9y^2

(3-3分之1t)^2=9-2t+1/9t^2

(2分之1m-5分之1n )^2=1/4m^2-1/5mn+1/25n^2

(r-h)^2=r^2-2rh+h^2

(4x+3y)^2=16x^2+24xy+9y^2

(-a-b)^2=a^2+2ab+b^2

(2分之1m-2)^2=1/4m^2-2m+4

(4分之1x-3分之2y)^2=1/16x^2-1/3xy+4/9y^2

(2x-2.5)^2=4x^2-10x+6.25