4x - y = -4 5x = 2y +1 how do I solve this using elimination?

Mathematics

2 answers:

TEA [102]2 years ago

6 0

Answer: x=-3, y=-8

Step-by-step explanation:

you will leave the first equation alone for now

the second, we will subtract 2y from both sides

5x-2y=1

now you system is

4x-y=-4

5x-2y=1

we will multiply the first equation with -2

-8x+2y=8

5x-2y=1

add both equations, we get -8x+5x=9, -3x=9,

x=-3

we will replace x with -3 in any equation, lets use 4x-y=-4,

-12-y= -4, -y=12-4, -y=8, y=-8

julia-pushkina [17]2 years ago

4 0

8x - 2y = -8
-5x + 2y = -1

3x = -9
x = -3

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postnew [5]

Answer:

$\frac{25}{4}$ (or 6.25)

Step-by-step explanation:

Let's do a simple square problem to see the relationship between the elements of the resulting equation...

$(x+3)(x+3) = x(x+3) + 3(x+3) = x^{2} +3x + 3x + 9 = x^{2} + 6x + 9$

As you see, the number of 'x' (6) is the double of the numeric part of the binomial expression (3), while the numeric-only part (9) is the square of the numeric part of the binomial expression (3).

So, if we look at the formula from the problem, we see the the number of 'x' is 5. To obtain the C value, we need to divide the 5 by 2... then get the square value of the result.

$\frac{5}{2} * \frac{5}{2} = \frac{25}{4}$ (or 6.25)