7x^2 - 16x - 8 = 0

using the quadratic formula x = [ -(-16)+/- sqrt((-16^2 - 4*7-8] / 2*7

= (16 +/1 sqrt 480) / 14

= 2.71, -0.42 to nearest hundredth

4 0

3 years ago

Ab= 6cm Ac=12cm <br> Calculate the length of Ad <br> Give your answer to 3 significant figures

Allisa [31]

Answer:

12.686cm

Step-by-step explanation:

By using pythagoras, we can find CB.

We know that $a^2+b^2=c^2$

Therefore, $12^2-6^2=CB^2$

$CB=\sqrt{108}$ (it has to be positive since it is distance)

now we look at triangle BCD and use SOH CAH TOA.

$Sin55=CB/CD\\Therefore, CD= 12.686$

8 0

3 years ago

Use the approach in Gauss's Problem to find the following sums of arithmetic sequences.

Svet_ta [14]

The total value of the sequence is mathematically given as

498501

<h3>The sum of the sequence is..?</h3>

Generally, the equation for Gauss's Problem is mathematically given as

The sum of an arithmetic series;

1+2+3+...+n= n(n+1)/2

Given an arithmetic sequence,

1+2+3+...+998,

Here,

n = 998

1+2+3+...+n=n(n+1)/2

1+2+3+...+998=98(998 + 1)/2

998 x 999 1+2+3+...+998 =2

1+2+3+...+998 = 498501

In conclusion, 498501 is the total value of the sequence.