Question
y=2-x 2. Without graphing determine whether each system has one solution , no solution, or infinitely many solutions. a) y=-5x-8 x+3y=4 e) 2x+y=4 2y=-4x+1 b) x-5y=3 2x-10y=-3 c) 3x+2y=-20 d) y=4-3x 6x+2y=8 3x+y=4 f) 6x-8=-2y g) 3x-2y=4 2x-3y=6
Solution
4.7
(325 Votes)
Lucy
Veteran ยท Tutor for 11 years
Answer
### a) One solution### b) No solution### c) One solution### d) Infinitely many solutions### e) No solution### f) One solution### g) One solution
Explanation
## Step 1: Analyze System a)### The first equation is already solved for
. Substitute
into the second equation:
. Simplify to
, which becomes
. Thus,
. Substitute
into
to get
. So, the solution is
, and the system has one solution.## Step 2: Analyze System b)### Multiply the first equation by 2:
, which simplifies to
. The second equation is
. Since the left sides are the same but the right sides are different, the system has no solution.## Step 3: Analyze System c)### Multiply the second equation by -1:
, which simplifies to
. Add this to the first equation:
. This simplifies to
, so
. Substitute this into the first equation:
, which simplifies to
. Thus,
, and
. The system has one solution
.## Step 4: Analyze System d)### Rewrite the first equation as
. This is the same as the second equation. Since both equations are the same, the system has infinitely many solutions.## Step 5: Analyze System e)### Rewrite the second equation as
. Multiply the first equation by 2:
, which simplifies to
. Since the left sides are the same but the right sides are different, the system has no solution.## Step 6: Analyze System f)### Rewrite the first equation as
. Divide by 2:
. The second equation can be rewritten as
. Multiply the first equation by 3:
. Subtract the second equation from this:
, which simplifies to
, so
. Substitute this into
:
, which means
. Thus,
. The system has one solution
.## Step 7: Analyze System g)### This system is already in standard form. We can use any method to solve. Multiply the first equation by 3 and the second equation by -2:
and
. Add these equations:
, so
. Substitute
into the first equation:
, so
, and
. The system has one solution
.