Which point is a solution to the following system of inequalities?

[tex]\[
\begin{cases}
-2x + 3y \geq 1 \\
-5x + 6y \leq 1
\end{cases}
\][/tex]

A. (6,6)
B. (7,8)
C. (8,7)
D. (9,7)



Answer :

To determine which point is a solution to the given system of inequalities, we will evaluate each point against both inequalities:

[tex]\[ \begin{cases} -2x + 3y \geq 1 \\ -5x + 6y \leq 1 \end{cases} \][/tex]

Let's check each point one-by-one:

1. Point (6, 6):

For the first inequality, substitute [tex]\( x = 6 \)[/tex] and [tex]\( y = 6 \)[/tex]:
[tex]\[ -2(6) + 3(6) = -12 + 18 = 6 \quad (\text{which is } \geq 1) \][/tex]
This point satisfies the first inequality.

For the second inequality, substitute [tex]\( x = 6 \)[/tex] and [tex]\( y = 6 \)[/tex]:
[tex]\[ -5(6) + 6(6) = -30 + 36 = 6 \quad (\text{which is not } \leq 1) \][/tex]
This point does not satisfy the second inequality.

2. Point (7, 8):

For the first inequality, substitute [tex]\( x = 7 \)[/tex] and [tex]\( y = 8 \)[/tex]:
[tex]\[ -2(7) + 3(8) = -14 + 24 = 10 \quad (\text{which is } \geq 1) \][/tex]
This point satisfies the first inequality.

For the second inequality, substitute [tex]\( x = 7 \)[/tex] and [tex]\( y = 8 \)[/tex]:
[tex]\[ -5(7) + 6(8) = -35 + 48 = 13 \quad (\text{which is not } \leq 1) \][/tex]
This point does not satisfy the second inequality.

3. Point (8, 7):

For the first inequality, substitute [tex]\( x = 8 \)[/tex] and [tex]\( y = 7 \)[/tex]:
[tex]\[ -2(8) + 3(7) = -16 + 21 = 5 \quad (\text{which is } \geq 1) \][/tex]
This point satisfies the first inequality.

For the second inequality, substitute [tex]\( x = 8 \)[/tex] and [tex]\( y = 7 \)[/tex]:
[tex]\[ -5(8) + 6(7) = -40 + 42 = 2 \quad (\text{which is not } \leq 1) \][/tex]
This point does not satisfy the second inequality.

4. Point (9, 7):

For the first inequality, substitute [tex]\( x = 9 \)[/tex] and [tex]\( y = 7 \)[/tex]:
[tex]\[ -2(9) + 3(7) = -18 + 21 = 3 \quad (\text{which is } \geq 1) \][/tex]
This point satisfies the first inequality.

For the second inequality, substitute [tex]\( x = 9 \)[/tex] and [tex]\( y = 7 \)[/tex]:
[tex]\[ -5(9) + 6(7) = -45 + 42 = -3 \quad (\text{which is } \leq 1) \][/tex]
This point satisfies the second inequality.

The point [tex]\((9, 7)\)[/tex] satisfies both inequalities.

Therefore, the point [tex]\((9, 7)\)[/tex] is a solution to the system of inequalities.