5x + y = 9....multiply by 7
10x - 7y = -18
----------------
35x + 7y = 63 (result of multiplying by 7)
10x - 7y = -18
----------------add
45x = 45
x = 45/45
x = 1
5x + y = 9
5(1) + y = 9
5 + y = 9
y = 9 - 5
y = 4
solution is : (1,4)
=========================
-4x + 9y = 9
x - 3y = -6 ....multiply by 4
----------------
-4x + 9y = 9
4x - 12y = -24 (result of multiplying by 4)
---------------add
- 3y = - 15
y = -15/-3
y = 5
x - 3y = -6
x - 3(5) = -6
x - 15 = -6
x = -6 + 15
x = 9
solution is : (9,5)
Answer:
Step-by-step explanation:
A) 5x - 7 = 5x becomes -7 = 0 if 5x is subtracted from both sides. This result is never true, so NO SOLUTION
B)3x−9=3(x−3) Performing the indicated multiplication, we get
3x - 9 = 3x - 9. This is always true, so there are INFINITELY MANY SOLUTIONS
C)2x−6=−2(x−3) Performing the indicated multiplication, we get
2x - 6 = -2x + 6. Adding 2x - 6 to both sides results in
4x - 12 = 0, or 4x = 12. Thus, the solution is x = 3. ONE SOLUTION
D)2x+6−5x=−3(x This equation is incomplete
Let
be the point on the ground to with the 18 foot guy is anchored and
the point on the ground to with the 21 foot guy is anchored.
We can conclude that the <span>the two wires at the points where they are anchored are
21 feet apart. Check the procedures in the picture attached.</span>
3. 28 Quarters and 5 dimes.
