7 • 15 = 7(10 + 5) = ____ + _____ = _____
It's supposed to be simplified.. If you ask me, it's just making it harder.
2007-10-15 07:03:29 · 15 answers · asked by TheSara~ 2 in Science & Mathematics ➔ Mathematics
7(10 + 5) = 7x10 + 7x5 = 70 + 35 = 105
They are teaching you the concept of distributing. In this case you are splitting 15 into its tens and units.
In fact, sometimes it is easier to multiply things in your head if you do it this way. For example, what is 7 x 35? If you think 7 times 30 = 210 and 7 x 5 = 35 you get 245.
It will be more useful when you have to things like:
7x + 35 --> 7(x + 5)
2007-10-15 07:06:46 · answer #1 · answered by Puzzling 7 · 1⤊ 0⤋
i think it's supposed to be:
7 * 15 = 7(10+5)
7 * 15 = 7(15)
7 * 15 = 105
(if * means multiply, then both sides of equation will end up equaling each other)
105 = 105
i believe... it's been a LONG time since i did algebra
2007-10-15 07:10:47 · answer #2 · answered by antoinette m 2 · 0⤊ 0⤋
Ok, this is what you do...
Distribute the 7 through the (10 + 5). The you can fill in the blanks-> 70 + 35 = 105. Done :)
2007-10-15 07:08:55 · answer #3 · answered by Cathy 1 · 0⤊ 0⤋
7*10 + 7*5 = 105
2007-10-15 07:06:18 · answer #4 · answered by dkappa95 4 · 1⤊ 0⤋
easy easy lemon squeezy
just multiplicate 7 by 10 and add it to the result of 7 by 5 like so
7(10+5)=70+35=105
2007-10-15 07:10:57 · answer #5 · answered by angelios_san 1 · 0⤊ 0⤋
70 + 35 = 105
2007-10-15 07:13:02 · answer #6 · answered by dreamer 3 · 0⤊ 0⤋
They're just having you break a number down (15) so that it's
not so hard to do the multiplying.
put the 7 inside the parenthesis. That's the distributive way.
(70+35)=105
2007-10-15 07:08:38 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Multiply 7 by each element in the parentheses, so
7x10 = 70 and 7x5 = 35
so the answer is 70 + 35 = 105
2007-10-15 07:06:55 · answer #8 · answered by Simonizer1218 7 · 1⤊ 0⤋
7 * 15 = 7(10 + 5)
Multiply the left side of the equation and add inside the parenthesis on the right side of the equation
105 = 7(15)
Multiply the right side of the equaton
105 = 105
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2007-10-15 07:13:38 · answer #9 · answered by SAMUEL D 7 · 0⤊ 0⤋
Algebra is a puzzle game -- it's a matter of pulling things apart and putting them back together in different ways.
7*15 is the same as 7 * (10 + 5) because (10 + 5) is the same as 15 -- it is a substitution.
Now, the rules for multiplication are that if you are multiplying one value (say 7) times the sum of two other values -- that's the same as multipling the first value against each of the other two -- and then adding those.
So, "seven times the sum of ten plus five" is the same as "the sum of (seven times ten) plus (seven times five)" -- and because they are the same, you can use the second equation instead of the first.
So, what is 7*10 + 7*5 ?
2007-10-15 07:08:42 · answer #10 · answered by coragryph 7 · 0⤊ 2⤋