Algebra

Algebra Changing the Subject to the Bold value Tricky Questions

R = c(a + b) R = c(a + b) Undo times c R = a + b c Undo subtract b R – b = a c

x = r ab x = r ab Undo divide by ab abx = r Undo times ax b = r ax

Q = P .x + y Q = P x + y Undo divide by (x + y) Q(x + y) = P Undo divide by Q x + y = P Q Undo add y x = P – y Q

r = √b r = √b Undo square root r² = b

R = √(ab) R = √(ab) Undo square root R² = ab Undo times a R² = b a

√( ) L = axb L = ax b √( ) Undo square root L² = ax b Undo divide by b L²b = ax Undo times a L²b = x a

X = ab² X = ab² Undo times a X = b² a Undo squared • √( ) X = b a

X = (ab)² X = (ab)² Undo squared • √ X = ab Undo times a • √ ( X) = b a NB: difference between this and previous result

A = ½(r + l) A = ½(r + l) Undo ½ 2A = r + l Undo add l 2A – l = r

A = a(b –c)x . A = a(b – c) x Undo divide by x Ax = a(b – c) Undo times a Ax = b – c a Undo subtract c Ax + c = b a

Q = rt + rs Q = rt + rs Factorise with Common Factor Q = r(t + s) Undo times (t + s) Q = r (t + s)