What to do? Curl up with a good book. Take a nature hike. Walk the dog. Get into a game of Ultimate Frisbee.
Multiply the first equation by 2 and subtract the second. You do this because you notice that 2*5=10 and doing this will eliminate the x variable.
2(5x+y) - (10x-7y) = 2(9) - (-18)
10x + 2y - 10x + 7y = 18 + 18 (use the distributive property to eliminate parentheses)
9y = 36 (collect terms)
y = 36/9 = 4 (divide both sides by 9)
5x + 4 = 9 (put the value for y in the first equation)
5x = 5 (subtract 4 from both sides)
x = 1 (divide both sides by 5)
The point of intersection of these two lines is (x, y) = (1, 4).
Multiply the first equation by 2 and subtract the second. You do this because you notice that 2*5=10 and doing this will eliminate the x variable.
2(5x+y) - (10x-7y) = 2(9) - (-18)
10x + 2y - 10x + 7y = 18 + 18 (use the distributive property to eliminate parentheses)
9y = 36 (collect terms)
y = 36/9 = 4 (divide both sides by 9)
5x + 4 = 9 (put the value for y in the first equation)
5x = 5 (subtract 4 from both sides)
x = 1 (divide both sides by 5)
The point of intersection of these two lines is (x, y) = (1, 4).
