Question

(1)当a=3,b=1时,分别计算代数式(a+b)^2与a^2+2ab+b^2的值.(2)当a=—3/4,b=1/2时,上述两个代数式的值又分别

Answer 1

(1)当a=3,b=1时,分别计算代数式(a+b)^2与a^2+2ab+b^2的值
(a+b)^2=(3+1)²=4²=16
a^2+2ab+b^2=3²+2(3)(1)+1²=9+6+1=16

(2)当a=—3/4,b=1/2时,
(a+b)^2=(-3/4+1/2)²=(-1/4)²=1/16
a^2+2ab+b^2=(-3/4)²+2(-3/4)(1/2)+(1/2)²=9/16-3/4+1/4=9/16-12/16+4/16=1/16

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

Answer 2

1) 16 16 2)1/16 1/16

Answer 3

根据完全平方公式有a^2+2ab+b^2=(a+b)^2
(1)
(a+b)^2=(3+1)²=4²=16 a^2+2ab+b^2=(a+b)^2=(3+1)²=4²=16

(2)
(a+b)^2=(-3/4+1/2)²=(-1/4)²=1/16 a^2+2ab+b^2=(a+b)^2=(-3/4+1/2)²=(-1/4)²=1/16