As you plug in those numbers for x (from left to right) y=
0
1
2
3
4
There are 3 methods to solve this. elimination substitution and graphing but i am going to use the elimination method.
x+2y=17
<u> x-y =2
</u> 0+3y =15 ( subtracted down to eliminate the x)( x-x=0, 2y-(-y)=3y, and 17-2=15)
3y=15 (divide both sides by 3 to solve for y)
y=5
<u>substitute the y=5 in any of the above equations and solve for x
ie... ( </u>meaning where you find y in the equation, u replace it with a 5)
it will be easier to solve for x in (x-y=2) so i will use that one.
x-(5)=2 ( add 5 on both sides to solve for x)
x=7
When subtracting a number from a negative (like question one) the subtraction sign will now be an addition sign.
1.
6-(-7)=13
For question 2, its simple subtraction. If you subtract a negative from positive, it'l be a negative.
2.
-3 - 3= -6
3.
-15 - 23 = -38
Now we combine my previous explanations. Subtracting a negative from a negative will be like adding (like in question 4)
4.
-9 - (-5)= -4
5.
5 - (-15)=20
6.
78-(-17)=95
Extra Info:
When adding a number (doesnt matter if positive or negative) to a negative it will turn into subtraction.
Examples:
6+(-9)=-3
-9+(-9)= -18
60 mm converts to 6 centimeters.
the ratio of 6 to 45 can be simplified to
2 : 15
