Question

Solve for x and y: y=2+7x −2x+6y=172 Select one:

Answer 1

It is pretty easy to eliminate the wrong answers by trying the answers in the equations.

a. 7 times 30 is way more than 4

c. 6 times 226 is way more than 172, even after subtracting 64

d. 7 times -74 is way less than 4

The appropriate choice is

... b. x=4, y=30

You can check it with your graphing calculator.

_____

Since you have an expression for y, you can substitute that into the second equation:

... -2x + 6(2+7x) = 172 . . . . substitute for y

... 40x = 160 . . . . . . . . . . . . eliminate parentheses, subtract 12, collect terms

... x = 4 . . . . . . this is sufficient to help you locate the correct answer