Y = 0.5x square - 2x-1.5

Y = 0.5x square - 2x-1.5

y=0.5x^2-2x-1.5
=0.5(x^2-4x-3)
=0.5((x-2)^2-7)
=0.5(x-2)^2-3.5

Formula for 2x square + 5x-4 = 0

x²+5x/2=2
x²+5x/2+25/16=2+25/16
(x+5/4)²=57/16
x+5/4=±√57/4
x=(-5-√57)/4,x=(-5+√57)/4

The greatest common factor of 5 and 9 is obtained by short division

Don't ask, 1

Given a > 0, b > 0, a + B = 1, find the minimum value of 1 / A + 1 / B + 1 / ab

Sum with high and middle derivatives: SN = 1 + 2x + 3x2 +. + NX (n-1)

Taking Sn as f (x), then f (x) = ∫ f (x) DX = x + x ^ 2 + x ^ 3 +... + x ^ n + C = (x-x ^ (n + 1)) / (1-x) + C, so f (x) = f '(x) = [(1 - (n + 1) x ^ n) (1-x) - (x-x ^ (n + 1)) (- 1)] / (1-x) ^ 2 = (1-x - (n + 1) x ^ n + (n + 1) x ^ (n + 1) + x-x ^ (n + 1)) / (1-x) ^ 2 = (1 - (n + 1) x ^ n + NX ^ (n + 1)) / (1-x) ^

The calculation of (28 + 2 / 7 × 7 / 8) × 1 / 4 needs a simple process

Original formula = (28 + 2 / 8) × 1 / 4
=28×1/4+1/4×1/4
=7+1/16
=7 1/16

A minus B, the difference is 1.5. A divided by B, and the quotient is also 1.5. How many are a, B? Please give the formula,

A-B=1.5
A/B=1.5
A=1.5B
1.5B-B=1.5
0.5B=1.5
B=3
A=1.5B=4.5

How to do 2 (0.3x + 4) - 5 (0.2x-7) = 9

2（0.3x+4）-5（0.2x-7）=9
0.6x+8-x+35=9
-0.4x=9-43
-0.4x=-34
x=85

(1) 398 times 402 + 4
(2) The second power of 102

(1)(398+2)*(402-2)+4
(2) 100 to the second power plus 2 to the second power plus 4

It is proved that the quadratic power of (M + 7) - (M + 5) can be divisible by 24

The second power of (M + 7) - (M + 5) ^ 2
=m^2+14m+49-m^2-10m-25
=4m+24
=4(m+6)
=24(m/6+1)
It's divisible by 24