Cho biểu thức A = (x + y)(x - y) + y^2. Thu gọn biểu thức. Tính giá trị biểu thức khi a = 100
1 cho bieu thuc A = (x+y)(x-y)+y^2
A thu gon bieu thuc
B tinh gia tri bieu thuc khi a = 100
2)phan tich cac da thuc sau thanh nhan tu
a)x^2-y^2-2x+2y
B) 4x^2-y^2+4x+1
Bai 2 tim x biet
A)(x-4)^2-(x-2)(x+2)=6
B) 2x^2 +3x-5=0
C)x(x-3)-2x+6=0
D) (x-1)^3-(x+3)(x^2-3x+9)+3(x^2-4)=2
Bai 3 cho tam giac abc vuong tai a (ab<ac) ke ah vuong goc voi bc tai h qua b ke duong thang vuong goc voi ab cat duong thang ah tai d tia ab va tia cd cat nhau tai e
A)chung minh be tren ba =de tren dc
B) qua e ke duong thang song song voi ac duong thang nay lan luot cat cac duong thang ad,bc tai i , k. Chung minh ei=ek
C ) goi nla giao diem cua eh va ac q la giao diem cua dn va bc goi p la giao diem cua bn va ad .chung minh na=nc va pq//bd
D) goi g la giao diem cua duong thang aqva cd qua q ke duong thang // coi ce cat duong thang ac tai t . Chung minh gh//ac va pt vuong goc voi ad
A thu gon bieu thuc
B tinh gia tri bieu thuc khi a = 100
2)phan tich cac da thuc sau thanh nhan tu
a)x^2-y^2-2x+2y
B) 4x^2-y^2+4x+1
Bai 2 tim x biet
A)(x-4)^2-(x-2)(x+2)=6
B) 2x^2 +3x-5=0
C)x(x-3)-2x+6=0
D) (x-1)^3-(x+3)(x^2-3x+9)+3(x^2-4)=2
Bai 3 cho tam giac abc vuong tai a (ab<ac) ke ah vuong goc voi bc tai h qua b ke duong thang vuong goc voi ab cat duong thang ah tai d tia ab va tia cd cat nhau tai e
A)chung minh be tren ba =de tren dc
B) qua e ke duong thang song song voi ac duong thang nay lan luot cat cac duong thang ad,bc tai i , k. Chung minh ei=ek
C ) goi nla giao diem cua eh va ac q la giao diem cua dn va bc goi p la giao diem cua bn va ad .chung minh na=nc va pq//bd
D) goi g la giao diem cua duong thang aqva cd qua q ke duong thang // coi ce cat duong thang ac tai t . Chung minh gh//ac va pt vuong goc voi ad