Question

Hey i need help with system of equations. i uploaded a doxs file you can onpen it in google docs

Answer 1

Answer:

PART A: x = 15 and y = -8

PART B: x = -5 and y = 3

Step-by-step explanation:

PART A:

The first equation is $x + y = 7\\y = 7 - x .............(a)$

The second equation is $3x - 2y = 1\\2y = 3x - 1$

Putting the value of y from (a) in the above equation, we get $2y = 3x - 1\\2(7 - x) = 3x - 1\\14 - 2x = 3x - 1\\x = 15$

From (a) we get y = 7 - x = 7 - 15 = -8

PART B:

Here the system of equations are $-x + 4y = 17........(a) and 3x - 5y = -30.........(b)$

From (a) we get, $x = 4y - 17$

Putting the above value of x in (b) we get, $3x - 5y = -30\\3(4y - 17) - 5y = -30\\12y - 51 - 5y = -30\\7y = 21\\y = 3$

Hence, $x = 4y - 17 = 12 - 17 = -5$