How do you solve 2y2=13y−15?

2 Answers
BDT Stu.
Mar 3, 2018

y=5ory=32

Explanation:

Make 0 the subject, so shift everything to one side of the inequality

2y2−13y+15

find two numbers that multiply to give 2⋅15 and add up to give −13.

Those two numbers are −3 and −10.

Write the equation in which −13 is a sum of −3 and −10.

2y2−3y−10y+15

Factorise

y(2y−3)−5(2y−3)

Factorise further

(y−5)(2y−3)

Jim G.
Mar 3, 2018

y=32 or y=5

Explanation:

rearrange into standard form

⇒2y2−13y+15=0←in standard form

using the a-c method of factorising

the factors of + 30 which sum to - 13 are - 10 and - 3

⇒2y2−10y−3y+15=0

⇒2y(y−5)−3(y−5)=0

⇒(y−5)(2y−3)=0

equate each factor to zero and solve for y

y−5=0⇒y=5

2y−3=0⇒y=32

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