Since he starts with (10x+7) dollars and is buying two pairs of jeans that each cost (4x-5) dollars you should subtract the cost of the jeans from his starting amount.
(10x+7)-2(4x-5)=
10x+7-8x+10=
2x+17
Answer:
-<u>One Equation</u>: is set equal to a variable
Example:
y = 2x + 1
x + 3y = -12
You already have y, plug it back into x + 3y = -12
x + 3(2x + 1) = -12
x + 6x + 3 = -12
7x + 3 = -12
(Subtract 3 from each side)
7x = -15
(Divide by 7)
x = - 2.14
-<u>No Equation</u>: is set equal to a variable
Example:
2x + y = 10
4× + 2y = -3
Subtract 2x from each side of 2x + y = 10, you should get y= -2x + 10. Now that you have found y, substitute y into 4x+ 2y = -3.
4x + 2(-2x + 10) = -3
4x + -4x + 20 = -3
(Subtract 20 from each side)
4x + -4x = -23
(Add 4x and -4x)
0 = -23
No Solution
<u>-Both</u><u> </u><u>Equations</u>: are set equal to a variable
Example:
y = x + 5
y = -x + 3
(you already have y so plug it into the other equation to solve for x)
-x + 3 = x + 5
(Add -x on both sides)
3 = 2x + 5
(subtract 5 from both sides)
-2 = 2x
(Divide by 2 on each side)
x = -1
I hope this helped!
Hey mate ,
here is your answer
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The average between any two rational numbers is also rational.
(7.7 + 7.9)/2 = 7.8
7.8 is rational because it can be written as a fraction with integer numerator and denominator (39/5) and it is also a terminating decimal.
