Question 66

If $$9x^2+16y^2=60$$ and $$3x+4y=6$$, then the value of xy is

Solution

Given : $$9x^2+16y^2=60$$ ------------(i)

and $$3x+4y=6$$

Squaring both sides, we get :

=> $$(3x+4y)^2=(6)^2$$

=> $$9x^2+16y^2+2(3x)(4y)=36$$

=> $$60+24xy=36$$ [Using (i)]

=> $$24xy=36-60=-24$$

=> $$xy=\frac{-24}{24}=-1$$

=> Ans - (A)

Create a FREE account and get:

Free SSC Study Material - 18000 Questions
230+ SSC previous papers with solutions PDF
100+ SSC Online Tests for Free

CAT Quant Questions | CAT Quantitative Ability

CAT Averages Mixtures Alligations Questions CAT Quadratic Equations Questions CAT Linear Equations Questions CAT Algebra Questions CAT Time, Distance and Work Questions

CAT DILR Questions | LRDI Questions For CAT

CAT Maxima-Minima Questions CAT Coins and Weights Questions CAT Quant Based DI Questions CAT Data change over a period Questions CAT Routes And Networks Questions

CAT Verbal Ability Questions | VARC Questions For CAT

CAT Para Jumbles Questions CAT Para Summary Questions CAT Vocabulary Questions CAT Critical Reasoning Questions CAT Odd One Out Questions

Follow us on

Boost your Prep!

Download App