Hey, i need help!! Giving brainliest!

What is the y-coordinate of the solution to this system of equations? 5x-8y=1 3x+6y=-21

Vanyuwa [196]

5x-8y=1...(1)
3x+6y=-21...(2)

(1)*3:
15x-24y=3...(3)

(2)*5:
15x+30y=-105...(2)

(3)-(2):
15x-24y-(15x+30y)=3-(-105)
15x-24y-15x-30y=108
-54y=108
y=-2

6 0

3 years ago

Solve each equation (quadratic pattern)

dusya [7]

Answer: x = 2

Step-by-step explanation:

$2^{2x}-2^x-12=0\\\\\text{Let u = }2^x\\\\u^2-u-12=0\\(u-4)(u+3)=0\\\\u-4=0\quad and\quad u+3=0\\u=4\qquad and\quad u=-3\\\\\text{Substitute u with }2^x\\2^x=4\qquad and \quad 2^x=-3\\2^x=2^2\quad and\quad \text{not possible}\\\boxed{x=2}$

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Answer: x = 0

Step-by-step explanation:

$3^{2x}+3^{x+1}-4=0\\\\3^{2x}+3^x\cdot3^1-4=0\\\\\text{Let u = }3^x\\u^2+3u-4=0\\\\(u+4)(u-1)=0\\\\u+4=0\quad and\quad u-1=0\\u=-4\qquad and\quad u=1\\\\\text{Substitute u with }3^x\\3^x=-4\qquad and\quad 3^x=1\\\text{not possible}\ and\quad 3^x=3^0\\.\qquad \qquad \qquad \qquad \boxed{x=0}$

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Answer: No Solution

Step-by-step explanation:

$4^x+6\cdot 2^x+8=0\\\\2\cdot 2^x+6\cdot 2^x+8=0\\\\\text{Let u = }2^x\\2u+6u+8=0\\8u+8=0\\8u=-8\\u=-1\\\\\text{Substitute u with }2^x\\2^x=-1\\\text{not possible}$

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Answer: No Solution

Step-by-step explanation:

$9^x=3^x-6\\\\3\cdot 3^x=1\cdot 3^x-6\\\\\text{Let u = }3^x\\\\3u=u-6\\2u=-6\\u=-3\\\\\text{Substitute u with }3^x\\3^x=-3\\\text{not possible}$

6 0

3 years ago

Jack and Jane are married and both work. However, due to their responsibilities at home, they have decided that they do not want

Sergeeva-Olga [200]

By setting up a system of equations we can easily solve this problem. Let's denote Jane's working hours with x and Jack's working hours with y. Since they don't want to work more than 65 hours, the first equation is x+y=65. The second equation is 14x+7y=770. By solving this system of equation $\left \{ {{x+y=65} \atop {14x+7y=770}} \right.$ , we find that y=20 hours, which is Jack's maximum working hours.

6 0

3 years ago

Mixed number eqivalent to 51/5

mafiozo [28]

51/5 is equivalent to 10 and 1/5.

6 0

3 years ago

if a coin is tossed 4 times, the odds of it coming up either heads every time or tails every time are 1:7.What is the probabilit

ivanzaharov [21]

Answer:

$1$

Explanation:

From the question, we have it that the probability of heads coming up every time or tail coming up every time is 1:7 if the coin is tossed in 4 tosses

What this means is that we have a probability of 1/8 of head showing up and a probability of 7/8 that a tail will show up in each toss of the coin

For four throws, it means all four are heads or all four are tails

If all four are heads, we have the probability of this happening as:

$\text{ (}\frac{1}{8})^{}$

if all four are tails, we have the probability as:

$\frac{7}{8}$

Now, the probability of either heads or all tails after 4 tosses will be:

$\text{ }\frac{1}{8}\text{ + }\frac{7}{8}\text{ = 1}$

8 0

1 year ago