Answer:
x - y = 4
x + y = 4
Step-by-step explanation:
Substitute x=4 and y=0 in every equation. If both sides of the equal sign are equal, (LS=RS, left side equals right side) then the graph intersects at (4,0).
- x - y = 4
- (4) - 0 = 4
-4 = 4
LS≠RS
x - y = 4
4 - 0 = 4
4 = 4
LS=RS
2 x + y = 7
2(4) + 0 = 7
8 = 7
LS≠RS
2 x + y = -7
2(4) + 0 = -7
8 = -7
LS≠RS
x + y = 4
4 + 0 = 4
4 = 4
LS=RS
2 x - y = 7
2(4) - 0 = 7
8 - 0 = 7
8 = 7
LS≠RS
Only x - y = 4 and x + y = 4 intersect at (4, 0).
Answer: AE=2
Step-by-step explanation:
a^2+b^2=c^2
Answer:
Sally is 63
Step-by-step explanation:
Represent Sally's age by x and Sam's by y.
Then x = 3y and x + y = 84.
Substituting 3y for x in the second equation, we get:
3y + y = 84, or 4y = 84, or y = 21. Since Sally is 3 times as old as Sam, we multiply 21 by 3: Sally's age is 3(21 years) = 63 years
