411,492 views
24 votes
24 votes
Is (10, 8) a solution to this system of equations?

2x - 5y = -20
X + 9y = 14
A
O a. Yes
b. No

User Frediy
by
3.0k points

2 Answers

13 votes
13 votes

No

Explanation:

Substitute value of x (10) & y (8) in both equation

x + 9y =14

10 + 9 x 8 = 82

(doesn't give us the output of 14)

2x - 5y = -20

2 x 10 - 5 x 8 = - 20

(this does, but both have to work)

Solution is at (-4.8,2.1):

2x +18y =28

2x - 5y = -20

(minus)

(18 - - 5 & 28 - - 20 those minus becomes a + )

23y = 48

÷23

y= 48/23

(2.1 to 1d.p)

Substitute y to find x

2x - 5y = -20

2x - 5 x 48/23 = - 20

2x - 240/23 = - 20

+240/23

2x = -220/23

÷2

x = - 110/23

X= -4.8 to 1d.p

(-110/23, 48/23)

Hope this helps!

User Greg Ruhl
by
3.4k points
20 votes
20 votes

Answer: No, there isn't anything showing that it is.

User Natdico
by
3.1k points