All categories

3 years ago

2x+y=20 6x-5y=12 substitution

1 answer:

6 0

$2x+y=20 \\
6x-5y=12 \\ \\
\hbox{solve the first equation for y:} \\
2x+y=20 \ \ \ |-2x \\
y=20-2x \\ \\
\hbox{substitute 20-2x for y in the second equation:} \\
6x-5(20-2x)=12 \\
6x-100+10x=12 \\
16x-100=12 \ \ \ |+100 \\
16x=112 \ \ \ |\div 16 \\
x=7 \\ \\
y=20-2x=20-2 \times 7=20-14=6 \\ \\
\boxed{(x,y)=(7,6)}$

You might be interested in

Miss Hoffman gave 90-cent tip to a waitress for serving a meal costing $6.00 what percent of the bill is her tip?

seraphim [82]

So,

Miss Hoffman gave 90 cents to the waitress.

Her meal, including the tip, cost $6, or 600 cents.

Her subtotal was represented by the quantity (600 - 90) cents.
600 - 90 = 510

Dividing 90 by 510 yields the percent tip that Miss Hoffman gave the waitress.
$\frac{90}{510}$
$\frac{9}{51}$
0.176 or 17.6% ≈ 18%

Miss Hoffman gave the waitress approximately 18% tip.

3 0

3 years ago

Anyone have answers to this whole sheet its literally due in 20 minutes

Minchanka [31]

Answer:

1. Communitave property

2. communitave property

1. distribute 2 to x and 10 to get ride of parenthesis

2. subtract 2x from the left to move it to the right so x is by itself

3. add 15 to both sides to cancel it out on one side, and move to the other.

4. divide by 5 on both sides so you can get the value of x

5. flip equation so it is in the x equals form

1. distribute 2 to the x and positive 3 on the left side, also distribute -4 to both x and -1 , to get rid of our parenthesis.

2. add 4x to both sides so it cancels out on one side and moves to the other ( our xs and numbers need to be on opposite sides)

3. subtract 4 on the left side to move it to the right side because again numbers on the right and letters on the left

4. divide by 6 on both sides of the equation to solve for x

5 0

3 years ago

Simplify. -5a-3b+8a+b

Misha Larkins [42]

The answer is
$3a - 2b$

6 0

3 years ago

A bicyde store costs $2400 per month to operate. The store pays an average of 570 per bike. The average selling price of each bi

amm1812

Answer:

It can't buy a bike for 570 and sell it fo 100. They'll just be losing money on top of rent

Step-by-step explanation:

8 0

3 years ago

Soren solves the quadratic equation x^2 + 8x – 9 = 0 using the quadratic formula. In which step did Soren make an error?

pochemuha

Answer:

step 3 didn't divide by 2

Step-by-step explanation:

in step

$\frac{ - 8 + \sqrt{100} }{2} = \frac{ - 8 + 10}{2} = 1 \\ \frac{ - 8 - \sqrt{100} }{2} = \frac{ - 8 - 10}{2} = - 9$

8 0

4 years ago