Algebra problems?

Question

Write in algebraic symbols.

three more than the sum of x and y?
c subtracted from the sum of x and y?
if one addend of x is c, what is the other addend?

Solve this equation.

The difference of two numbers is 18, and their sum is 90. Find the two numbers.

Answer 1

1) x+y+3 --> we don't need parentheses

2) x+y-c --> same property used above, we don't need parenths

3) x= c+y
It can really be whatever

4) x-y=18
x+y=90
2x=108 (you just add the two equations)
108/2
x=54

Answer 2

three more than the sum of x and y? (x+y) < 3
c subtracted from the sum of x and y? (x-y) -c
if one addend of x is c, what is the other addend? 1 + x = c
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The difference of two numbers is 18, and their sum is 90. Find the two numbers.
(a - b = 18
(a + b = 90
2a = 108
a = 108 : 2
a = 54
a+ b = 90
54 + b = 90
b = 90 -54
b = 36
Answer: a = 54; b = 36
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Answer 3

three more than the sum of x and y?
(x+y)+3
Since sum is addition and 3 more is addition

c subtracted from the sum of x and y?
(x+y)-c
Since the sum is addition and c is taken from that

Solve this equation.

The difference of two numbers is 18, and their sum is 90. Find the two numbers.

x-y=18
x+y=90 therefore, y = 90 - x

x - (90 - x) = 18
x - 90 + x = 18
2x = 108
x = 108/2

x = 54
y = 90 - 54

Answer 4

1) 3 > x + y

( x+ y ) - c

1 + x = c ?

2) x - y = 18 (1)
x + y = 90 (2)

first equation become x = 18 + y (1)'

subtitute (1)' in (2) we have : 18 + y+ y = 90
2y = 90 - 18
2y = 72
y = 36

substitute y=36 in (2)


We have x +36 = 90 => x = 54

verification => 54 -36 = 18 (true)
54 +36 = 90 (true)

Answer : x = 54 and y = 36

Answer 5

1.x+y+3
2.x+y-c
3.could not follow