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3 years ago

Math help please!!!!!!!!!!!!!!!!!!!!!!

Mathematics

1 answer:

lora16 [44]3 years ago

5 0

I think the third one

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Ax+by=(a-b) , bx - ay =(a+b) simultaneous linear equations using cross multiplication

Molodets [167]

Answer:

$x=1\,,\,y=-1$

Step-by-step explanation:

Given: $ax+by=a-b\,,\,bx-ay=a+b$

To solve: the given linear equations

Solution:

Consider the equations:

$A_1x+B_1y+C_1=0\\A_2x+B_2y+C_2=0$

By method of cross multiplication:

$\frac{x}{B_1C_2-B_2C_1}=\frac{y}{C_1A_2-C_2A_1}=\frac{1}{A_1B_2-A_2B_1}$

For equations: $ax+by=a-b\,,\,bx-ay=a+b$

$ax+by-(a-b)=0\\bx-ay-(a+b)=0$

Take $A_1=a\,,\,B_1=b\,,\,C_1=-(a-b)\,,\,A_2=b\,,\,B_2=-a\,,\,C_2=-(a+b)$

So,

$\frac{x}{-b(a+b)-a(a-b)}=\frac{y}{-b(a-b)+a(a+b)}=\frac{1}{-a^2-b^2}\\\frac{x}{-ab-b^2-a^2+ab}=\frac{y}{-ab+b^2+a^2+ab}=\frac{1}{-(a^2+b^2)}\\\frac{x}{-(a^2+b^2)}=\frac{y}{a^2+b^2}=\frac{1}{-(a^2+b^2)}\\\frac{x}{-(a^2+b^2)}=\frac{1}{-(a^2+b^2)}\,,\,\frac{y}{a^2+b^2}=\frac{1}{-(a^2+b^2)}\\x=1\,,\,y=-1$

6 0

3 years ago

Solve the inequality. Enter the answer as an inequality that shows the value of the variable; for example f > 7, or 6 < w.

OLEGan [10]

X + 4 > 13 would equal to x > 9

4 0

3 years ago

If the variance is 28 kg2 what is the standard deviation?

ikadub [295]

Answer:

The standard deviation is 5.29 kg.

Step-by-step explanation:

The standard deviation is the square root of the variance. Mathematically, we have that:

$S(X) = \sqrt{V(X)}$

In this problem, we have that:

$V(X) = 28$

$S(X) = \sqrt{V(X)}$

$S(X) = \sqrt{28}$

$S(X) = 5.29$

The standard deviation is 5.29 kg.

7 0

3 years ago

Fabian harvests 10 pounds of tomatoes from his garden. He needs 225 pounds to make a batch of soup. If he sets aside 2.8 pounds

nadya68 [22]

He can make 3 batches of soup.

Starting with 10 pounds of tomatoes and taking out the number of pounds he sets aside for spaghetti sauce, 2.8, we have:
10-2.8 = 7.2 pounds left.

0.2 is read as "two tenths," so 7.2 = 7 2/10

We divide this remaining number of pounds by 2 2/5 for each batch of soup:

7 2/10 ÷ 2 2/5

Convert each to an improper fraction:
72/10 ÷ 12/5

Multiply by the reciprocal:
72/10 × 5/12 = 360/120 = 3

5 0

3 years ago

What’s four plus four minus thirty two

Tanya [424]

The answer is 4+4-32=-24

8 0

3 years ago

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