You multiply using the multiplication table. Multiplication is one of the four basic operations in arithmetic, along with addition, subtraction, and division. Multiplication can actually be considered repeated addition, and you can solve simple multiplication problems by adding repeatedly. For larger numbers, you'll want to do long multiplication, which breaks the process down into repeated simple multiplication and addition problems. You can also try a shortcut version of long multiplication by splitting the smaller number in the problem into tens and ones, but this works best when the smaller number is between 10 and 19.
Use this systems of equations to solve:
x = first antifreeze
y = second antifreeze

Isolate y.
x + y = 15
Subtract x from both sides.
y = -x + 15
Substitute y into the other equation.
.2x + .12(-x + 15) = .18(15)
Simplify.
.2x - .12x + 1.8 = 2.7
Subtract 1.8 from both sides.
.08x = .9
Divide both sides by .08
x = 11.25
Substitute x in the equation that we isolated y in.
y = -11.25 + 15
y = 3.75
11.25 L of the first antifreeze and 3.75 L of the second.
X - 9y = -45 i’m not sure what line ? but this is in standard form
Answer:
<u>$4,680</u>
Step-by-step explanation:
<u>Rate</u> : 10 dollars a week
- Per year : 10 x 52 = $520
- 9 x 520 = $4,680
You will have saved up <u>$4,680</u> in 9 years.