It is currently 27 Nov 2020, 09:56

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Solve each of the following equations for x. (a) 5x−7=28 (b)

Author Message
TAGS:
Founder
Joined: 18 Apr 2015
Posts: 13909
GRE 1: Q160 V160
Followers: 315

Kudos [?]: 3680 [0], given: 12935

Solve each of the following equations for x. (a) 5x−7=28 (b) [#permalink]  24 May 2019, 00:49
Expert's post
Solve each of the following equations for x.

(a) $$5x−7=28$$

(b) $$12−5x=x+30$$

(c) $$5(x+2)=1−3x$$

(d) $$(x+6)(2x−1)=0$$

(e) $$x^2+5x−14=0$$

(f) $$x^2 −x−1=0$$

[Reveal] Spoiler: OA
(a) 7 (b) −3 (c) - $$\frac{9}{8}$$ (d) $$-6,\frac{1}{2}$$ (e) $$-7,2$$ (f) $$\frac{1+\sqrt{5}}{2}, \frac{1-\sqrt{5}}{2}$$

Math Review
Question: 6
Page: 244
Difficulty: medium

_________________

New to the GRE, and GRE CLUB Forum?
GRE: All you do need to know about the GRE Test | GRE Prep Club for the GRE Exam - The Complete FAQ
Posting Rules: QUANTITATIVE | VERBAL
FREE Resources: GRE Prep Club Official LinkTree Page | Free GRE Materials - Where to get it!! (2020)
Free GRE Prep Club Tests: Got 20 Kudos? You can get Free GRE Prep Club Tests
GRE Prep Club on : Facebook | Instagram

Questions' Banks and Collection:
ETS: ETS Free PowerPrep 1 & 2 All 320 Questions Explanation. | ETS All Official Guides
3rd Party Resource's: All Quant Questions Collection | All Verbal Questions Collection
Books: All GRE Best Books
Scores: The GRE average score at Top 25 Business Schools 2020 Ed. | How to study for GRE retake and score HIGHER - (2020)
How is the GRE Score Calculated -The Definitive Guide (2021)
Tests: GRE Prep Club Tests | FREE GRE Practice Tests [Collection] - New Edition (2021)
Vocab: GRE Prep Club Official Vocabulary Lists for the GRE (2021)

GRE Instructor
Joined: 10 Apr 2015
Posts: 3907
Followers: 164

Kudos [?]: 4771 [1] , given: 70

Re: Solve each of the following equations for x. (a) 5x−7=28 (b) [#permalink]  24 May 2019, 13:02
1
KUDOS
Expert's post
Carcass wrote:
Solve each of the following equations for x.

(a) $$5x−7=28$$

(b) $$12−5x=x+30$$

(c) $$5(x+2)=1−3x$$

(d) $$(x+6)(2x−1)=0$$

(e) $$x^2+5x−14=0$$

(f) $$x^2 −x−1=0$$

[Reveal] Spoiler: OA
(a) 7 (b) −3 (c) - $$\frac{9}{8}$$ (d) $$-6,\frac{1}{2}$$ (e) $$-7,2$$ (f) $$\frac{1+\sqrt{5}}{2}, \frac{1-\sqrt{5}}{2}$$

Math Review
Question: 6
Page: 244
Difficulty: medium

(a) $$5x−7=28$$
Add 7 to both sides: $$5x=35$$
Divide both sides by 5 to get: $$x=7$$

(b) $$12−5x=x+30$$
Add 5x to both sides: $$12=6x+30$$
Subtract 30 from both sides: $$-18=6x$$
Divide both sides by 6 to get: $$-3=x$$

(c) $$5(x+2)=1−3x$$
Expand left side: $$5x+10=1−3x$$
Add 3x to both sides: $$8x+10=1$$
Subtract 10 from both sides: $$8x=-9$$
Divide both sides by 8 to get: $$x = -\frac{9}{8}$$

(d) $$(x+6)(2x−1)=0$$
This means EITHER $$x+6=0$$ OR $$2x-1=0$$
Solve $$x+6=0$$ to get $$x=-6$$
Solve $$2x-1=0$$ to get $$x = \frac{1}{2}$$

(e) $$x^2+5x−14=0$$
Factor: $$(x+7)(x-2)=0$$
So, EITHER $$x=-7$$ OR $$x=2$$

(f) $$x^2−x−1=0$$
Apply the quadratic formula to get:
$$x=\frac{1+\sqrt{5}}{2}$$ or $$x=\frac{1-\sqrt{5}}{2}$$

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com

Re: Solve each of the following equations for x. (a) 5x−7=28 (b)   [#permalink] 24 May 2019, 13:02
Display posts from previous: Sort by