All categories

3 years ago

Will mark brainliest!

Mathematics

2 answers:

nikklg [1K]3 years ago

7 0

Answer:

b = −1

b = −4

Step-by-step explanation:

Common Factor

Divide both sides of the equation by the same term

Use the quadratic formula

Serggg [28]3 years ago

3 0

Answer:

-1 or -4

Step-by-step explanation:

first all you have to do is to multiply 12 by 3b² to give you 36b² and then find a number(x) multiplied by another number(y) to give you 36b² and those two numbers must sum up to give you 15b

doing this, we would have our two numbers to be

12b and 3b

replace these two numbers with 15b in the equation

3b² + 12b + 3b + 12=0

(3b²+12b) + (3b+12)=0

3b(b+4)+3(b+4)=0

note: the numbers in the brackets must be the same

(3b+3)(b+4)=0

therefore, 3b + 3= 0 or b + 4= 0

3b+3= 0

3b=-3

b=-3/3

b=-1

b+4=0

b=-4

You might be interested in

Sarah is carrying out a series of experiments which involve using mcreasing amounts of a chemical. In the

Marianna [84]

Sarah is carrying out a series of experiments which involve using increasing amounts of a chemical. In the first experiment she uses 6g of the chemical and in the second experiment she uses 7.8 g of the chemical

(i)Given that the amounts of the chemical used form an arithmetic progression find the total amount of chemical used in the first 30 experiments

(ii)Instead it is given that the amounts of the chemical used for a geometric progression. Sarah has a total of 1800 g of the chemical available. Show that the greatest number of experiments possible satisfies the inequality: $1.3^N \leq 91$ and use logarithms to calculate the value of N.

Answer:

(a)963 grams

(b)N=17

Step-by-step explanation:

(a)

In the first experiment, Sarah uses 6g of the chemical

In the second experiment, Sarah uses 7.8g of the chemical

If this forms an arithmetic progression:

First term, a =6g

Common difference. d= 7.8 -6 =1.8 g

Therefore:

Total Amount of chemical used in the first 30 experiments

$S_n=\dfrac{n}{2}[2a+(n-1)d] \\S_{30}=\dfrac{30}{2}[2*6+(30-1)1.8] \\=15[12+29*1.8]\\=15[12+52.2]\\=15*64.2\\=963$ grams$

Sarah uses 963 grams in the first 30 experiments.

(b) If the increase is geometric

First Term, a=6g

Common ratio, r =7.8/6 =1.3

Sarah has a total of 1800 g

Therefore:

Sum of a geometric sequence

$S_n=\dfrac{a(r^N-1)}{r-1} \\1800=\dfrac{6(1.3^N-1)}{1.3-1} \\1800=\dfrac{6(1.3^N-1)}{0.3}\\$Cross multiply\\1800*0.3=6(1.3^N-1)\\6(1.3^N-1)=540\\1.3^N-1=540\div 6\\1.3^N-1=90\\1.3^N=90+1\\1.3^N=91$