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3 years ago

What is 7 times as much as the sum of 1/3 + 4/5

1 answer:

riadik2000 [5.3K]3 years ago

8 0

Lets write the problem info into an equation and solve step by step:
7(1/3 + 4/5)
the minimum common multiple of 3 and 5 is 15, so we multiply and divide the fractions by a proper number to convert them to be divided by 15 so is easier to add them:
(1/3)(5/5) = (1*5)/(3*5) = 5/15
(4/5)(3/3) = (4*3)/(5*3) = 12/15
so we substitute in the original equation:
7(1/3 + 4/5)
= 7(5/15 + 12/15)
= 7(17/15)
= (7*17)/15
= 119/15

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Using Cramer's rule to solve linear systems.

Rzqust [24]

Answer: Last Option

$x=2,\ y=-5$

Step-by-step explanation:

Cramer's rule says that given a system of equations of two variables x and y then:

$x =\frac{Det(A_X)}{Det(A)}$

$y =\frac{Det(A_Y)}{Det(A)}$

For this problem we know that:

$Det(A) = |A|=\left|\begin{array}{ccc}4&-6\\8&-2\\\end{array}\right|$

Solving we have:

$|A|= 4*(-2) -(-6)*8\\\\|A|=40$

$Det(A_X) = |A_X|=\left|\begin{array}{ccc}38&-6\\26&-2\\\end{array}\right|$

Solving we have:

$|A_X|=38*(-2) - (-6)*26\\\\|A_X|=80$

$Det(A_Y) = |A_Y|=\left|\begin{array}{ccc}4&38\\8&26\\\end{array}\right|$

Solving we have:

$|A_Y|=4*(26) - (38)*8\\\\|A_Y|=-200$

Finally

$x =\frac{|A_X|}{|A|} = \frac{80}{40}\\\\x=2$

$y =\frac{|A_Y|}{|A|} = \frac{-200}{40}\\\\y=-5$

4 0

3 years ago

Write the equation of the line that passes through the points (0,–2) and (4,5). Put

Ber [7]

Step-by-step explanation:

5+2/4-0=7/4

7/4=y+2/×-0

y=7x/4-2

8 0

3 years ago

Sam is renting one of two cars to go on a 300-mile trip. The first car can travel 75 miles on 5 gallons of gas. The second car c

djverab [1.8K]

First let’s establish a few things, The first car can travel 300 miles with 20 gallons of gas, if 14 gallons of gas costs 49.49 then for ever gallon of gas Sam is paying 3 dollars and 53.5 cents. That means for 20 gallons, Sam will need around 71$ for the entire trip if he uses the first car.

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2 years ago

Solve. –4t ≤ 48 A. t ≥ –12 B. t ≤ –12 C. t ≥ 12 D. t ≤ 12

Oksana_A [137]

$-4t \leq 48 \ \ \ : |(-4) \\ \\ t \geq 12$

\\\ Ben

3 0

3 years ago

Alvin had some marbles in a box. He kept 1/3 of them and gave the remainder to Joyce and Sean. Joyce got 5/8 of the remainder. W

Zigmanuir [339]

First, Alvin gave Joyce and Sean 2/3 of the remainder, to solve first find the common denominator, which in this case is 24. Then, 1/3=?/24, 24/3=8 so it is 8/24 for the total given by Alvin. Joyce got 5/8, 5/8=?/24, 24/8=3,3 x 5=15, 15/24.
15/24 - 8/24= 7/24 is the answer

6 0

3 years ago