Question

Tính nhanh

a) \(x^2+\frac{1}{2}x+\frac{1}{16}\)Với x = 99,75

b) x² - y² - 2y - 1 Với x = 93, y = 6

Answer 1

a)=(x+1/4)^2=100^2=10000

b) =x^2-(y+1)^2=(x-y-1)(x+y+1)=86.100=8600

Answer 2

bằng 20

Answer 3

a. x² + \(\frac{1}{2}x\)+ \(\frac{1}{16}\)

= x² + 2.x\(\frac{1}{4}\)+ \(\left(\frac{1}{4}\right)^2\)

= (x + \(\frac{1}{4}\))²

= (99,75 + 0,25)²

= 100² = 10000

b. x² - y² - 2y - 1

= x² - (y² + 2y + 1)

= x² - (y + 1)²

= (x + y + 1)(x - y - 1)

= (93 + 6 + 1)(93 - 6 - 1)

= 100 . 86 = 8600

Answer 4

a)\(x^2+\frac{1}{2}x+\frac{1}{16}=x^2+2.\frac{1}{4}x+\frac{1}{4^2}\)\(=\left(x+\frac{1}{4}\right)^2=\left(99,75+\frac{1}{4}\right)^2\)\(=100^2=1000\)

b)\(x^2-y^2-2y-1=x^2-\left(y+1\right)^2\)\(=\left(x-y-1\right)\left(x+y+1\right)\)\(=\left(93-6-1\right).\left(93+6+1\right)\)

=86.100=8600