Question

Which ordered pair (p, r) is a solution to the given system of linear equations?
5p-3r=1
8p+6r=4
A.(–1, –2)
B. (–2, –1)
C.(2/9,1/3)
D.(1/3,2/9)

Answer 1

Easiest way : Put the value from the choices into two equations

Answer 2

Best way : Eliminate a variable from the system of equation, by multiplying one with a constant, to make the coefficient of a variable equal. Then eliminate

Answer 3

is it a?

Answer 4

5p - 3r = 1 /*2
8p + 6r = 4
__________
10p - 6r = 2
8p + 6r = 4
__________
10p - 6r + 8p + 6r = 2 + 4
18p = 6
p = 6/18
p = 1/3

5p - 3r = 1
5 * 1/3 - 3r = 1
5/3 - 3r = 1
5/3 - 1 = 3r
5/3 - 3/3 = 3r
2/3 = 3r
r = 2/9

(p, r) = (1/3, 2/9)

The correct result would be (1/3, 2/9).

Answer 5

thank you