Answer:
3 + 4 = 7 which is true.
Step-by-step explanation:
Whenever you have an equation with a plain variable (that is, no exponent included), there is only one number that will work when substituted for x.
To solve it, you have to "undo" what is done to the variable. You also go in the reverse order of operations, so you do the addition/subtract first, then multiplication/division.
You also have to do the same to both sides, kind of like keeping a balance scale in balance.
In this case, we subtract 4 from both sides first:
3x + 4 -4 = 7 - 4
The + 4 - 4 cancel each other out, so you get:
3x = 3
3x means "3 times x" so you divide by 3 to undo it. I will use the / to indicate division:
3x / 3 = 3 /3
so 1x = 1.
Since 1x is "1 times x" it is the same as x by itself, so:
x=1
AND, if we substitute 1 back into the original equation (the asterisk stands for multiply):
3 * 1 + 4 = 7
3 * 1 is 3, so:
3 + 4 = 7 which is true.
1 is the only number that works.
Hope this helped.
2x + 2y = 6 . . . . . (1)
x + 3y = -1 . . . . . (2)
(1) x 3 => 6x + 6y = 18 . . . . . (3)
(2) x 2 => 2x + 6y = -2 . . . . . (4)
(3) - (4) => 4x = 20
x = 20/4 = 5
Answer:
19.1 miles
Step-by-step explanation:
The situation given represents a right triangle.
Thus, we would use trigonometric function to find how far north the boat travelled.
Let's represent how far the boat travelled north with "x".
Thus:
Reference angle = 23°
Opposite = x
Adjacent = 45 miles
Apply TOA:
Tan 23° = Opp/Adj
Tan 23° = x/45
Multiply both sides by 45
45 × Tan 23° = x
x = 45 × Tan 23°
x = 19.1013667
x = 19.1 miles (nearest tenth of a mile)
