Question

use the solution method to the system of equations 8x+5y=9 , y=x+7

Answer 1

Answer:

$x=-2\\y=5$

Step-by-step explanation:

Given Equations:

$8x+5y=9$   Equation:1

$y=x+7$       Equation:2

Using substitution method:

Put the value of 'y' in Equation:1

$8x+5y=9$

$8x+5(x+7)=9\\\\8x+5x+35=9$

Adding the like terms:

$13x+35=9$

Subtracting '35' both sides:

$13x+35-35=9-35\\\\13x=-26$

Dividing '13' both sides:

$x=-26/13\\\\x=-2$

Put the value of 'x' in Equation:2

$y=x+7$

$y=-2+7\\\\y=5$

The solution of the equation is:

$x=-2\\y=5$

Answer 2

Answer:

x = -2

y = 5

Step-by-step explanation:

8x+5y=9 ........... (i)

y=x+7 ..................(ii)

Substitute (y = x + 7) in equation (I)

8x + 5(x + 7) = 9

8x + 5x + 35 = 9

13x + 35 = 9

13x = 9 - 35

13x = -26

Divide both sides by 13 to make x the subject :

x = -26 / 13

x = -2

Substitute x = -2 in equation (ii)

y = x + 7

y = -2 + 7

y = 5.

TO CHECK:

x = -2

y = 5

8x+5y=9

8(-2) + 5(5) =

-16 + 25 = 9.