How do i solve 3x+y=13, 5x-2y=18 using the substitution method

1 answer:

7 0

$\left\{\begin{array}{ccc}3x-y=13&\text{multiply both sides by (-2)}\\5x-2y=18\end{array}\right\\\underline{+\left\{\begin{array}{ccc}-6x+2y=-26\\5x-2y=18\end{array}\right}\\.\qquad-x=-8\qquad\text{change the signs}\\.\qquad\boxed{x=8}\\\\\text{Put the value of x to the first equation}\\\\3(8)-y=13\\\\24-y=13\qquad\text{subtract 24 from both sides}\\\\-y=-11\qquad\text{change the signs}\\\\\boxed{y=11}\\\\Answer:\ \boxed{x=8\ and\ y=11\to(8,\ 11)}$

You might be interested in

one day, gale and hector each recorded temperatures outside their homes. function g shows tempatures, in F, gale recorded c hour

myrzilka [38]

Hector, 4 degrees, Gale

8 0

3 years ago

Read 2 more answers

21 lbs of potatoes cost $231. How much would 28 lbs cost?

bija089 [108]

Answer:

$308

Step-by-step explanation:

First, you have to find out how much it costs per pound, so you would divide 231 by 21. each pound of potatoes costs $11. so 11 x 28 would make it $308.

5 0

2 years ago

Read 2 more answers

Find the inverse function of

shtirl [24]

Answer:

$f(x) = 20x - 4 \\ substitute \: y \: for \: f(x) \\ y = 20x - 4 \\ interchange \: x \: and \: y \\ x = 20y - 4 \\ swap \: the \: sides \: of \: the \: equation \\ 20y - 4 = x \\ move \: the \: constant \: to \: the \: right \: hand \\ 20y = x + 4 \\ divide \: both \: sides \: by \: 20 \\ y = \frac{1}{20} x + \frac{1}{5} \\ substitute \: f {}^{ - 1} (x) \: for \: y \\ f {}^{ - 1} (x) = \frac{1}{20} x + \frac{1}{5}$

The domain of the inverse of a relation is the same as the range of the original relation. In other words, the y-values of the relation are the x-values of the inverse.

Thus, domain of f(x): x∈R = range of f¯¹(x)

and range of f(x): x∈R =domain of f¯¹(x)

3 0

2 years ago

1/2 to exponent of 4

Neporo4naja [7]

Answer:

0.0625 is the answer.

Hope it helps you!!!

4 0

2 years ago

Solve: 2x-10= 40<br>Solve for X

Arturiano [62]

The correct answer is B

4 0

2 years ago

Read 2 more answers