更新时间2022-06-24 14:21:49
(1-4y)(1+4y)+(1+4y)²
=1-(4y²)+1+2(4y)+(4y)²
=2+8y
=2+8*2/5
=5.2
//
2(3x+1)(1-3x)-(x-2)(2+x)
=2[1-(3x)²]-(x²-2²)
=2-18x²-x²+4
=6-19x²
=6-19*2²
=6-76
=-70
(1-4y)(1+4y)+(1+4y)^2
=1-16y^2+1+8y+16y^2
=2+8y
y=2/5
2+8*2/5
=52/5
2(3x+1)(1-3x)+(x-2)(2+x)
=2*(3x-9x^2+1-3x)+(2x+x^2-4-2x)
=2*(1-9x^2)+x^2-4
=2-18x^2+x^2-4
=-17x^2-2
x=2
-17*2^2-2
=-70