Past papers › WAEC · 2022 · May/June · General Maths · Paper 1 › Question 34 Question WAEC General Maths 2022 Objective Expressions, formulae & change of subject Quadratics & their graphs Expressions, formulae & change of subject, Quadratics & their graphs
WAEC 2022 · Paper 1 · Q34 Simplify 2 − 18 m 2 1 + 3 m \dfrac{2 - 18m^2}{1 + 3m} 1 + 3 m 2 − 18 m 2
A 2 ( 1 + 3 m ) 2(1 + 3m) 2 ( 1 + 3 m ) B 2 ( 1 + 3 m 2 ) 2(1 + 3m^2) 2 ( 1 + 3 m 2 ) C 2 ( 1 − 3 m ) 2(1 - 3m) 2 ( 1 − 3 m ) D 2 ( 1 − 3 m 2 ) 2(1 - 3m^2) 2 ( 1 − 3 m 2 )
Worked solution (try it first) Take out 2 on top:
2 − 18 m 2 = 2 ( 1 − 9 m 2 ) 2 - 18m^2 = 2(1 - 9m^2) 2 − 18 m 2 = 2 ( 1 − 9 m 2 ) .
Use the difference of two squares:
1 − 9 m 2 = ( 1 − 3 m ) ( 1 + 3 m ) 1 - 9m^2 = (1 - 3m)(1 + 3m) 1 − 9 m 2 = ( 1 − 3 m ) ( 1 + 3 m ) .
Cancel
1 + 3 m 1 + 3m 1 + 3 m :
2 ( 1 − 3 m ) 2(1 - 3m) 2 ( 1 − 3 m ) , option C.
Watch out
The bracket that cancels is 1 + 3 m 1 + 3m 1 + 3 m 1 − 3 m 1 - 3m 1 − 3 m 1 + 3 m 1 + 3m 1 + 3 m Report a problem with this question