1) 23
2) 3
3) 6x+5 (I am not sure what they ask for)
4) -12+x
5) -56x + 16
6) -90+80x
7) -18x+45y-27
8) 6x+24y-42
9) 2/3w+x-1
10) -1.2wy +3y
While it's pretty obvious to most of us that
-13x=90-2y
-6x=48-2y
is a system of linear equations, it'd be well to include that info plus the instructions "solve this system of linear equations."
Subtract the 2nd equation from the first:
-13x=90-2y
+6x=-48+2y
-----------------------
-7x = 42. Then x = -42/7, or x = 6.
Now subst. 6 for x in either one of the given equations. Suppose we use the 2nd equation:
-6x=48-2y
Then -6(6)=48-2y, or -36 = 48 - 2y, or 2y = 48+ 36 = 84. Then y = 42.
The solution is (6, 42).
Subtraction property of equality
2/3y = -6
2/3y × 3/2 = -6 × 3/2
multiplication property of equality
y = -9
