21= -7/9w
W=??
Note: The 7/9 is a fraction. 7 over 9.
How do I solve this math question?
2009-06-13 6:07 am
回答 (13)
2009-06-13 6:10 am
✔ 最佳答案
Is the -7/9 the coefficient of w then? so it's:
21 = (-7/9)w
If so, you need to multiply both halves by the reciprocal of the coefficent, which is -9/7, so we have:
21(-9/7) = w
-27 = w
2009-06-13 1:14 pm
21 = -7/9w
i.e 21*9 = -7/9w*9
i.e 189 = -7w
i.e -189/7 = w
i.e -27 = w
i.e w = -27
i.e 21*9 = -7/9w*9
i.e 189 = -7w
i.e -189/7 = w
i.e -27 = w
i.e w = -27
2009-06-13 1:13 pm
Tip #1: If you multiply a fraction by the denominator (the bottom part) you get rid of the bottom part. For example, 1/2 * 2 = 1 (you just got rid of the bottom 2).
Tip #2: If you do the same thing to BOTH SIDES of any equation then the equality remains. For example, 4 = 2 + 2 stays an equality if I add 10 to both sides: 5 + 10 = 2 + 2 + 10, right?
So use tip #1 and tip #2 to solve your equation.
21 * 9 = -7/9w * 9 (tip #2)
21 * 9 = -7w (tip #1)
189 = -7w
w = -27
Tip #2: If you do the same thing to BOTH SIDES of any equation then the equality remains. For example, 4 = 2 + 2 stays an equality if I add 10 to both sides: 5 + 10 = 2 + 2 + 10, right?
So use tip #1 and tip #2 to solve your equation.
21 * 9 = -7/9w * 9 (tip #2)
21 * 9 = -7w (tip #1)
189 = -7w
w = -27
2009-06-13 1:12 pm
multiply 9 to both sides
189=-7w
divide -7 to both sides
-27= w
189=-7w
divide -7 to both sides
-27= w
2009-06-13 1:10 pm
w=-27
2009-06-13 1:14 pm
21 = 7/9w
7/9w = 21
7w = 21/9 =7/3
w = 7/3/7 = 1/3
7/9w = 21
7w = 21/9 =7/3
w = 7/3/7 = 1/3
2009-06-13 2:27 pm
21 = -7/9(w)
21 = -7w/9
9(21) = -7w
w = 189/(-7)
w = -27
21 = -7w/9
9(21) = -7w
w = 189/(-7)
w = -27
2009-06-13 1:26 pm
w= -27
2009-06-13 1:16 pm
21 = -7/9 w
Divide (-7/9) from both sides. Giving:
21 ÷ (-7/9) = w
When dividing two fractions we must reciprocate (flip over) the fraction and multiply. Thus:
21 Ã (-9/7) = w
Do this using a calculator (or mentally). This gives:
-27 = w
Hope this helps :D
Divide (-7/9) from both sides. Giving:
21 ÷ (-7/9) = w
When dividing two fractions we must reciprocate (flip over) the fraction and multiply. Thus:
21 Ã (-9/7) = w
Do this using a calculator (or mentally). This gives:
-27 = w
Hope this helps :D
收錄日期: 2021-05-01 12:28:49
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