Education.com

# Tip #30 to Get a Top ACT Math Score (page 2)

By Brian Leaf
McGraw-Hill Professional

1. E Multiply coefficients (numbers in front of the letters) and add exponents. So 2x2 · 3x3y · 3x3y = (2 · 3 · 3)(x2+3+3)(y1+1) = 18x8y2. Remember that y really means y1.
2. G When you multiply variables, like m, you add the exponents; and when you divide m's, you subtract the exponents. So, m3 × 2m5 × IMG
3. D Springboard review: when you see something that can simplified, do it. x3 = 27 simplifies to x = 3, since 33 = 27. Then just plug 3 in for each x: 33 + 32 = 27 + 9 = 36.
4. K (–3x3y4)4 = (–3)4(x3)4(y4)4 = 81x12y16. Careless Error Buster: Remember that the (–3) also gets the exponent.
5. B 186,000 is in miles per second. To get miles per minute, multiply by 60. And then to get miles per hour, multiply by 60 again. Finally, to get 3 hours, multiply by 3: 186,000 × 60 × 60 × 3 = 2,008,800,000. Then just type each answer choice into your calculator to see which one matches best. Choice B, 2,000,000,000, is closest. A number written in the form 2 × 109 is called scientific notation, and just means 2 with 9 zeros, or 2,000,000,000. So even if a number in scientific notation was too big for your calculator, just remember that it means the first number with as many zeros as the number in the exponent, like 5 × 104 = 50,000.
6. H Since mp = x and np = y, then xy = (mp)(np) = (mn)p. Notice that this time I did not add the exponents because m and n are different letters, and we only add exponents when the base is the same.

Go to: Tip #31

150 Characters allowed

### Related Questions

#### Q:

See More Questions

### Today on Education.com

#### WORKBOOKS

May Workbooks are Here!

#### ACTIVITIES

Get Outside! 10 Playful Activities