20 points 3 math questions please help with these math questions
2 answers:
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Answer:
20)
19)
18)
17)
16)
15)
14)
13)
12)
11)
Step-by-step explanation:
20) {−2x - y = −9
{5x - 2y = 18
⅖[5x - 2y = 18]
{−2x - y = −9
{2x - ⅘y = 7⅕ >> New Equation
__________
[Plug this back into both equations above to get the x-coordinate of 4];
_______________________________________________
19) {−5x - 8y = 17
{2x - 7y = −17
−⅞[−5x - 8y = 17]
{4⅜x + 7y = −14⅞ >> New Equation
{2x - 7y = −17
_____________
[Plug this back into both equations above to get the y-coordinate of 1];
_______________________________________________
18) {−2x + 6y = 6
{−7x + 8y = −5
−¾[−7x + 8y = −5]
{−2x + 6y = 6
{5¼x - 6y = 3¾ >> New Equation
____________
[Plug this back into both equations above to get the y-coordinate of 2];
_______________________________________________
17) {−3x - 4y = 2
{3x + 3y = −3
__________
[Plug this back into both equations above to get the x-coordinate of −2];
_______________________________________________
16) {2x + y = 20
{6x - 5y = 12
−⅓[6x - 5y = 12]
{2x + y = 20
{−2x + 1⅔y = −4 >> New Equation
____________
[Plug this back into both equations above to get the x-coordinate of 7];
_______________________________________________
15) {6x + 6y = −6
{5x + y = −13
−⅚[6x + 6y = −6]
{−5x - 5y = 5 >> New Equation
{5x + y = −13
_________
[Plug this back into both equations above to get the x-coordinate of −3];
_______________________________________________
14) {−3x + 3y = 3
{−5x + y = 13
−⅓[−3x + 3y = 3]
{x - y = −1 >> New Equation
{−5x + y = 13
_________
[Plug this back into both equations above to get the y-coordinate of −2];
_______________________________________________
13) {−3x + 3y = 4
{−x + y = 3
−⅓[−3x + 3y = 4]
{x - y = −1⅓ >> New Equation
{−x + y = 3
________
_______________________________________________
12) {−3x - 8y = 20
{−5x + y = 19
⅛[−3x - 8y = 20]
{−⅜x - y = 2½ >> New Equation
{−5x + y = 19
__________
[Plug this back into both equations above to get the y-coordinate of −1];
_______________________________________________
11) {x + 3y = 1
{−3x - 3y = −15
___________
[Plug this back into both equations above to get the y-coordinate of −2];
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