Question

Which ordered pair is a solution of the inequality?

Y-1<2x
a. (3,7)
b. (1,8)
c. (2,7)
d. (3,-11)

Answer 1

d. (3, -11)

Explanation:

`y-1<2x\qquad\text{add 1 to both sides}\\\\y<2x+1\\\\\text{Substitute the coordinates of the points and check the inequality:}\\\\a.\ (3,\ 7)\\7<2(3)+1=6+1=7\qquad\text{FALSE}\\\\b.\ (1,\ 8)\\8<2(1)+1=2+1=3\qquad\text{FALSE}\\\\c.\ (2,\ 7)\\7<2(2)+1=2+1=5\qquad\text{FALSE}\\\\d.\ (3,\ -11)\\-11<2(3)+1=6+1=7\qquad\text{TRUE}`