Algebra
posted by Betty on .
Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this.
3x – 5y = 61
7x – 5y = 9

Eq1: 3X  5Y = 61
Eq2: 7X  5Y = 9
Multiply both sides of Eq1 by 1 and
add the 2 Eqs:
3X + 5Y = 61
7X  5Y = 9
Sum: 10X = 70,
X = 70 / 10 = 7.
Substitute 7 for x in Eq2:
7*7  5Y = 9,
49  5Y = 9,
5Y = 9 + 49 = 40,
Y = 40 / 5 = 8.
Solution set = (7, 8).