Question

Using substitution to solve the system below, what expression should be substituted into the first equation? 2x-4y=-4 and x+2y=8

Answer 1

Answer:

Given the system of equation:

$2x-4y=-4$                    ......[1]

$x+2y=8$                      ......[2]

we can rewrite equation [2] as;

$x = 8-2y$                ......[3]

Substitute equation [3] into [1] to eliminate x, and solve for y;

$2(8-2y)-4y = -4$

Using distributive property: $a\cdot (b+c) = a\cdot b+ a\cdot c$

$16-4y -4y = -4$

Combine like terms;

16 - 8y = -4

Add 4 to both sides we have;

20 - 8y = 0

Add 8y to both sides we have;

20 = 8y

Divide 8 to both sides we have;

$y = 2.5$

Substitute the y-value in [3] we have;

$x = 8-2(2.5)$

x = 8 - 5 = 3

Therefore, the  expression should be substituted into the first equation is, $x = 8-2y$  and also the value of x = 3 and y = 2.5

Answer 2

Answer:

Step-by-step explanation:

Choices?